Open English Wordnet
Nouns
(n)complex, coordination compounda compound described in terms of the central atom to which other atoms are bound or coordinated
(n)building complex, complexa whole structure (as a building) made up of interconnected or related structures
Adjectives
(s)complicated, complexdifficult to analyze or understand“a complicated problem”, “complicated Middle East politics”, “he's more complex than he seems on the surface”