At the moment you can only search for an icon using the unique label for it with no alternate terms.

So when I searched for an icon called "check" or "tick" I go no results, because the icon I wanted is called "Completion100"

Likewise when I searched for "ban" or "denied" or "wrong" I got no results because I the icon I wanted is called "Delete"

PS: It'd be cool if you used FontAwesome's much larger set of icons instead!