These are really poorly defined actually, I suggest looking into the history of these words. I refer to myself as a warlock because of it's history, and it's the one I know the best.
I'm female, I use magic, I don't see gods as useful, and i'm a warlock.
The history of warlock, is that it originally meant pact breaker, referring to breaking the pact with a god for humans to not use magic.
I use the term, because I use magic in defiance of any Devine being. I do not worship gods, because I see them as silly and useless to me. Until I have a deity who worships and serves me, I will never use a single one in my magic. In this I break the same pact that the word was originally intended for, and in fact, I blatantly do so.