complex

//ˈkɒmpleks//
B2Frequency Level 6Neutral
Visual representation of complex

Adjective

more complexComparative
most complexSuperlative
1

consisting of many different and connected parts; intricate or complicated

The human brain is a complex organ with billions of interconnected neurons.

2

not easy to analyze or understand; difficult

The problem is too complex for me to solve alone.

Noun

complexesPlural
1

a group of similar buildings or facilities on the same site

The sports complex includes a swimming pool, tennis courts, and a gym.

2

a related group of emotionally significant ideas that are completely or partly repressed and that cause psychic conflict leading to abnormal mental states or behavior

He has an inferiority complex that affects his relationships.

3

a group of related things or concepts

The university has a complex of buildings dedicated to scientific research.