What's the meaning of 'Fanboy'

Well there are two meanings.

Fanboy: a boy that is a fan about comics, science fiction, movies, or tv shows.

But, I think the one you wanted is:

For

And

Nor

But

Or

Yet

There is also an s in fanboys which is so, but u only asked for fanboy.

These are some of the most common prepositions.

A fanboy is a boy who is a fan of something, like a TV show or a band.