I've read somewhere that if complex is an adjective, its second syllable is stressed (com-plex), while for noun, the first one (com-plex). But e.g. this link says that adjective can also sound as noun. I also remember that my teacher (many years ago) said "com-plex object", although complex is an adjective here.
I guess stress depends on context of usage. So, what are the cases for stressing first or second syllable in adjective complex? How do I determine which syllable has to be stressed?
For example, how are "complex numbers", "complex object", "complex problem" pronounced?
Best Answer
The OED has accent on com for both noun and adjective, but accent on plex for verb. What verb, you ask. Well, it is obsolete or rare except in chemistry, where it means "form a complex with".
Here in America, I have heard the plex accent version on occasion. But nothing as simple as the noun/adjective distinction proposed by Ruslan.
My American dictionary has only com accent for the noun, but both possible accents for the adjective or the verb.
My advice: use accent com for the adjective, no one will object (or even notice).
Note: combined forms may accent the plex ... complexity, complexification, non-complex, super-complex.