Nouns

(n)complex, compositea conceptual whole made up of complicated and related parts“the complex of shopping malls, houses, and roads created a new town”
(n)complex, coordination compounda compound described in terms of the central atom to which other atoms are bound or coordinated
(n)complex(psychoanalysis) a combination of emotions and impulses that have been rejected from awareness but still influence a person's behavior
(n)building complex, complexa whole structure (as a building) made up of interconnected or related structures

Adjectives

(a)complexcomplicated in structure; consisting of interconnected parts“a complex set of variations based on a simple folk melody”, “a complex mass of diverse laws and customs”
(s)complicated, complexdifficult to analyze or understand“a complicated problem”, “complicated Middle East politics”, “he's more complex than he seems on the surface”