someone who isn't an instantly recognisable celebrity but isn't one of the masses. Someone that has some sort of celebrity status but their status is temporary - like someone who is on Big Brother or a weather girl or a drag queen
That guy is the guy who just got evicted from Big Brother - he's such a semi-celebrity.
I feel like Im a semi-celebrity
You think you're a celebrity, but you're a nobody...not even a semi-celebrity
She is sooooo semi-celebrity