Thesaurus.com
Dictionary.com
Definitions

complex

[kuhm-pleks, kom-pleks, kom-pleks] / kəmˈplɛks, ˈkɒm plɛks, ˈkɒm plɛks /
ADJECTIVE
involved, intricate
Synonyms
STRONGEST
complicated convoluted
STRONG
composite compound conglomerate manifold mosaic motley multiple multiplex
WEAK
circuitous compounded confused elaborate entangled heterogeneous knotty labyrinthine mingled miscellaneous mixed mixed-up multifarious multiform tangled tortuous variegated
Antonyms
STRONGEST
simple
STRONG
single uniform unmixed
WEAK
apparent clear direct discernible easy evident homogeneous obvious plain
ADJECTIVE
difficult to understand
Synonyms
STRONGEST
complicated convoluted disturbing intricate obscure perplexing sophisticated
STRONG
byzantine winding
WEAK
Daedalean Gordian abstruse bewildering circuitous confused crabbed cryptic discursive disordered enigmatic entangled excursive hidden impenetrable inscrutable interwoven involved jumbled knotted knotty labyrinthine mazy meandering mingled mixed muddled paradoxical puzzling rambling recondite round-about sinuous snarled tangled tortuous undecipherable unfathomable
Antonyms
STRONGEST
easy simple
WEAK
apparent clear direct discernible evident homogeneous obvious plain uniform
NOUN
composite, aggregate
Synonyms
STRONGEST
compound network structure system
STRONG
association conglomerate ecosystem entanglement group organization scheme syndrome synthesis totality
Antonyms
STRONG
division separation
NOUN
psychological problem
Synonyms
STRONG
anxiety fear fixation hang-up insanity mania neurosis obsession phobia preoccupation repression
WEAK
a thing about something exaggerated reaction fixed idea idée fixe
Antonyms
STRONG
balance sanity

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Political news outlet Axios, citing administration officials, reported that any "supermax" prison complex at the site would have to be built from scratch -- putting the total cost at somewhere around $2 billion.

From Barron's • Apr. 3, 2026

Weir incorporates complex mathematical concepts into his storytelling in “Project Hail Mary,” but the cerebral approach doesn’t seem to be scaring many readers away.

From The Wall Street Journal • Apr. 3, 2026

They also received specialised courses in battlefield medicine, complex recovery operations and weapons.

From BBC • Apr. 3, 2026

Connecting Tehran to the city of Karaj, the $400-million bridge was Iran’s largest, and was often regarded as one of the most prominent, expensive and complex engineering endeavors in the Middle East.

From Los Angeles Times • Apr. 3, 2026

This complex, state-of-the-art industrial mining station had a name.

From "The Wild Robot Protects" by Peter Brown

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.