hardness
gb/hˈɑɹdnəs/ us/hˈɑɹdnəs/
B1
English
~ 9300
Senses
0 senses
Noun
B1
property
1
firm, solid quality of something
How hard and firm something is when you touch or try to press or cut it.
Usage pattern:
the hardness of [material]
Common mistake:
Learners sometimes use *strong* instead of *hardness* when talking about materials, saying things like *the strong of the metal* instead of *the hardness of the metal*. Use *hardness* to talk about how difficult something is to press, cut, or scratch.
Synonyms
firmness (Focuses on how solid or stable something feels, not specifically on cutting or scratching.)
Antonyms
softness (Describes a material that is easy to press, cut, or deform.)
Collocations
the hardness of the wood
|surface hardness
|rock hardness
|varying hardness
|measure the hardness
|test the hardness
Themes
science
|daily_life
|technology
|core_vocabulary
Examples
- The hardness of the countertop makes it ideal for heavy kitchen work.
- You can tell the quality of the steel by its hardness.
- The geologist compared the hardness of different rocks at the site.
- This pencil lead has a greater hardness, so it makes lighter lines.
- The ball’s hardness affects how high it bounces on the court.
Learner examples
- The hardness of the table makes it good for writing.
- We checked the hardness of the metal before using it.
- This rock has more hardness than that one.
- The knife cannot cut the glass because of its hardness.
- I like the hardness of this mattress; it feels strong and firm.
Noun
B2
property
2
degree of difficulty of something
How difficult a task, problem, or situation is.
Usage pattern:
the hardness of [task / problem / situation]
Common mistake:
Learners usually say *difficulty* instead of *hardness*, which is fine and more common. However, do not say *the hard of the exam*; use *the hardness of the exam* or simply *the exam was hard*.
Synonyms
difficulty (Most common general term; *hardness* is slightly more formal and less frequent in this sense.)
Antonyms
ease (Describes when something can be done with little effort or difficulty.)
Collocations
the hardness of the exam
|the hardness of the training
|the hardness of the questions
|assess the hardness
|varying levels of hardness
Themes
education
|work
|thinking
|core_vocabulary
Examples
- Students complained about the hardness of the final exam.
- The hardness of the training program surprised many new recruits.
- We underestimated the hardness of implementing the new software system.
- Researchers evaluated the hardness of the puzzles used in the study.
- The game lets you adjust the hardness of each level.
Learner examples
- The hardness of the test was too high for me.
- They talked about the hardness of life in the big city.
- We did not expect the hardness of the work.
- You can change the hardness of the game in the menu.
- The teacher explained the hardness of the project at the start.
Noun
C1
property
3
harsh, unkind quality in people
The quality of being cold and not kind or gentle toward other people.
Usage pattern:
the hardness of [someone / someone's voice / someone's heart]
Common mistake:
Learners sometimes confuse *hardness* with *strength* in this context. *Hardness* here means being cold or unkind, not being strong or brave.
Synonyms
harshness (Often used for tone of voice or treatment of others; *hardness* suggests emotional coldness or lack of pity.)
Antonyms
kindness (Highlights warm, caring behavior, the opposite of emotional hardness.)
Collocations
the hardness of his heart
|a certain hardness in her voice
|emotional hardness
|a cold hardness
|hardness towards others
Themes
emotions
|character
|relationships
Examples
- There was a new hardness in his voice when he spoke to them.
- Despite her reputation for hardness, she quietly helped many people.
- The film explores the hardness of his character beneath a charming surface.
- Over the years, his experiences gave him a certain hardness toward strangers.
- Her hardness in negotiations left the other side with little room to move.
Learner examples
- I heard a hardness in his voice when he said my name.
- Her hardness makes it difficult to talk about my problems.
- The teacher’s hardness surprised the new students.
- He tried to hide the hardness in his heart.
- People did not like the hardness she showed to her team.
Noun
technical
B2
property
4
mineral content of water
How much mineral, like calcium and magnesium, is in water, making it ‘hard’ or ‘soft’.
Usage pattern:
the hardness of [water]
Common mistake:
Learners sometimes say *strong water* instead of *hard water*. Use *water hardness* to talk about the level of minerals, and *hard water* for water with high hardness.
Synonyms
mineral content (A broader scientific term; *hardness* is the specific effect of those minerals in water.)
Antonyms
softness (Refers to water with low mineral content, the opposite of hard water.)
Collocations
water hardness
|high hardness
|low hardness
|measure water hardness
|test for hardness
Themes
science
|environment
|home
|daily_life
Examples
- The hardness of the tap water leaves white marks on the shower door.
- We installed a filter to reduce the hardness of our well water.
- Water hardness can shorten the life of household appliances.
- The report shows that water hardness in this area is quite high.
- They tested the hardness of the water before choosing a softener.
Learner examples
- The hardness of the water makes it difficult to wash my hair.
- We checked the water hardness in our new home.
- High water hardness can damage the washing machine.
- A water softener can lower the hardness of the water.
- The city measures water hardness every year.
Noun
technical
C1
property
5
measured hardness of materials
In science and engineering, a number that shows how much a material can resist scratching or a small dent on its surface.
Usage pattern:
the hardness of [metal / material]
Common mistake:
Learners may confuse everyday *hardness* (how something feels) with technical hardness, which is a measured property using specific tests like Rockwell or Brinell.
Synonyms
scratch resistance (Describes one important aspect of hardness but does not always include resistance to indentation.)
Antonyms
softness (In materials science, indicates a low resistance to scratching or indentation.)
Collocations
Brinell hardness
|Rockwell hardness
|Vickers hardness
|Mohs hardness
|hardness scale
|hardness test
Themes
science
|engineering
|technology
Examples
- The alloy was selected for its high hardness and wear resistance.
- According to the Rockwell hardness test, this steel is suitable for cutting tools.
- The Mohs scale compares the hardness of different minerals.
- Heat treatment significantly increased the hardness of the sample.
- Engineers measured the hardness at several points on the surface.
Learner examples
- We tested the hardness of the metal in the lab.
- This tool needs a very high hardness.
- The Mohs scale shows the hardness of minerals from 1 to 10.
- Heat can change the hardness of steel.
- They used a machine to check the hardness of the surface.
Noun
vulgar
C1
property
6
rigidity during sexual arousal
How firm or hard the penis becomes during sexual arousal.
Usage pattern:
[someone]’s hardness
Common mistake:
Learners may not realize this sense is sexual and can sound vulgar in casual conversation. In medical or polite talk, phrases like *erectile function* or *firmness* are usually preferred.
Synonyms
firmness (In sexual or medical contexts, *firmness* is more neutral and less vulgar than *hardness*.)
Antonyms
flaccidity (Technical term for a soft, non-erect state, the opposite of hardness in this context.)
Collocations
maintain hardness
|loss of hardness
|achieve hardness
|full hardness
|improve hardness
Themes
health
|sexuality
|body
Examples
- He spoke to his doctor about problems maintaining hardness during sex.
- Some medications can affect hardness and sexual performance.
- The study measured changes in hardness over several minutes.
- Stress and anxiety may reduce hardness even when desire is present.
- They advertised a product claiming to improve hardness and stamina.
Learner examples
- He had trouble keeping his hardness, so he went to a doctor.
- Some men worry about their hardness as they get older.
- The medicine is used to help men reach normal hardness.
- Smoking can have a bad effect on hardness.
- The doctor asked questions about his hardness during sex.
Grammar
Dictionary form
hardness
IPA
GB/hˈɑɹdnəs/
US/hˈɑɹdnəs/
Syllables & stress
hard - ness (2 syllables)
Stress on 1st syllable (hard)
Word forms
Noun
- Base: hardness
- Plural: hardness, hardnesses
Word family
Expressions
hardness of heart
1/hˈɑɹdnəs əv hˈɑɹt/
idiom
literary
lack of compassion or pity
A strong lack of kindness or pity in a person.
Examples
- The story shows the king’s hardness of heart toward his people.
- She could not understand his hardness of heart in the face of such suffering.
hardness test
1/hˈɑɹdnəs tˈɛst/
fixed phrase
technical
test of a material’s hardness
A test used in science or engineering to see how well a material resists a scratch or a small dent.
Examples
- The engineer performed a hardness test on the new alloy.
- Different hardness tests are used for metals, plastics, and ceramics.
Mohs hardness scale
1/mˈɑs hˈɑɹdnəs skˈeɪl/
fixed phrase
technical
scale for mineral hardness
A numbered list from 1 to 10 that shows how hard different minerals are by how easily they can be scratched.
Examples
- Quartz has a value of 7 on the Mohs hardness scale.
- Geology students must memorize the Mohs hardness scale for their lab work.
Rockwell hardness test
1/ɹˈɑkwˌɛl hˈɑɹdnəs tˈɛst/
fixed phrase
technical
Rockwell method for hardness
A special test that pushes a small object into a material with force to find out how hard the material is.
Examples
- The parts were checked with a Rockwell hardness test before shipping.
- Standards specify which Rockwell hardness test should be used for each metal.
water hardness
1/wˈɔtɚ hˈɑɹdnəs/
fixed phrase
technical
level of minerals in water
How much mineral (like calcium and magnesium) is in water, making it ‘hard’.
Examples
- High water hardness can cause scale to build up in pipes.
- We installed a system to reduce water hardness in our house.