complex
gb/kˈɑmplɛks/ us/kˈɑmplɛks/
A2
English
~ 1300
Senses
0 senses
adjective
B1
property
1
Complicated or intricate
Having many parts that are connected in a way that makes it hard to understand.
Usage pattern:
[something] is complex
Common mistake:
Learners sometimes confuse 'complex' with 'complicated' without knowing that 'complex' can be neutral, while 'complicated' may sound slightly negative.
Synonyms
complicated (Very close in meaning; often interchangeable, but 'complicated' can imply unnecessary difficulty.)
Antonyms
simple (Describes something easy to understand with few parts.)
Collocations
complex problem
|complex system
|complex process
|complex situation
Themes
description
|thinking
|problem-solving
|core_vocabulary
|education
Examples
- The tax laws are incredibly complex.
- She explained a complex theory in simple terms.
- Managing a large team can be a complex task.
- The machine has a complex design that requires skilled technicians.
Learner examples
- The game rules are complex.
- This is a complex question.
- The story has a complex plot.
Noun
A2
entity
2
Connected set of buildings
A group of buildings that are used together for one purpose.
Usage pattern:
[a] complex
Common mistake:
Learners may confuse 'complex' (group of buildings) with 'complicated' (difficult).
Synonyms
facility (A place for a specific purpose, but not necessarily multiple connected buildings.)
Collocations
apartment complex
|sports complex
|shopping complex
Themes
places
|architecture
|housing
|core_vocabulary
Examples
- They live in a large apartment complex near the park.
- The sports complex includes a swimming pool and tennis courts.
- The new shopping complex attracts many visitors.
Learner examples
- We live in an apartment complex.
- The sports complex has a big pool.
- There is a new shopping complex in town.
Noun
B2
entity
3
Psychological emotional issue
A strong feeling or worry about something that affects how you think or act.
Usage pattern:
have a [type] complex
Common mistake:
Learners may misinterpret this as meaning 'complicated' rather than an emotional issue.
Synonyms
fixation (A persistent focus on something, though not always emotional.)
Collocations
inferiority complex
|guilt complex
Themes
psychology
|emotions
|health
Examples
- He has an inferiority complex about his height.
- She developed a guilt complex after the accident.
- The therapist helped him work through his complexes.
Learner examples
- He has an inferiority complex.
- She has a guilt complex.
- I think he has a complex about his job.
Noun
technical
C1
entity
4
Chemical structure of bonded units
In chemistry, a group of atoms joined around a central atom or molecule.
Synonyms
compound (A more general term for a substance made of two or more elements.)
Collocations
coordination complex
|metal complex
Themes
science
|chemistry
Examples
- The scientist studied the structure of the coordination complex.
- This metal complex is used in catalysis.
- Chlorophyll is a magnesium-containing complex.
Learner examples
- Water is not a complex, it is a compound.
- The chemist made a new metal complex.
- A coordination complex has a central atom.
Grammar
Dictionary form
complex
IPA
GB/kˈɑmplɛks/
US/kˈɑmplɛks/
Syllables & stress
com - plex (2 syllables)
Stress on 1st syllable (com)
Word forms
Adjective
- Base: complex
Noun
- Base: complex
- Plural: complexes
Word family
Expressions
inferiority complex
1/ˌɪnfɪɹiˈɔɹɪti kˈɑmplɛks/
fixed phrase
Feeling less capable than others
A feeling that you are not as good as other people.
Examples
- He developed an inferiority complex after failing the exam.
- Her constant comparisons gave her an inferiority complex.
Oedipus complex
1/ˈɛdɪpəs kˈɑmplɛks/
fixed phrase
technical
Freudian theory about child-parent desire/rivalry
In psychology, when a young child feels love for the parent of the opposite sex and dislike for the parent of the same sex.
Examples
- Freud introduced the idea of the Oedipus complex.
- The novel explores themes similar to the Oedipus complex.
superiority complex
1/sˌupɪɹiˈɔɹɪti kˈɑmplɛks/
fixed phrase
unrealistic belief of superiority
A strong and often unhealthy belief that you are better than other people.
Examples
- His arrogance is due to a superiority complex.
- His constant bragging makes it clear he has a superiority complex.
- People with a superiority complex often look down on others.
- People with a superiority complex often hide deep feelings of insecurity.
- Her colleagues joked that her superiority complex was bigger than her office.