It's not grammatically incorrect, stop saying that. Grammatically it is both an adjective and a noun. And it is accurate. Your problem with it is that you think it's gross, and you are being disingenuous saying it's grammatically incorrect.
What? It is grammatically incorrect to use it in specific contexts. This is not even arguable. Just because a word is both an adjective and a noun does not mean you use it interchangeably between syntax. That's not how language works.
I don't think you understand what grammar is, son.
I can say "hippos are reptiles." It's wrong, but it's not gramatically incorrect.
No, you clearly do not understand what grammar is.
To be real; far be it from me to be a prescriptivist and clearly say one thing or another is 100% grammatically incorrect, however if you were to ask any native english speaker-
What sentence sounds more grammatically correct:
"The female over there is about to buy a donut"
"The woman over there is about to buy a donut"
The majority of people would label the second sentence as more grammatically correct than the first.