I have been studying the word not lately and noticed it is not a conjunction just by itself and it is actually an adverb. Now, when we use following types of sentences, what is not's grammatical function:
- If I was the boss, I would buy good quality stuff, not the shit one.
- I wanna live like a G, not like a coward.
- I want real money mate, not fake.
Oxford dictionary says, not is used with auxiliary verb. In the above mentioned examples, I don't think not modifies AV, it more likely looks like a comparison operator, like rather. It appears like not is a conjunction like rather. Please explain where am I getting it wrong.