'showstopper' definitions:

An act so striking or impressive that the show must be delayed until the audience quiets down [syn: show- stopper, showstopper, stopper]

Something that is strikingly attractive or has great popular appeal; "she has a show-stopper of a smile"; "the brilliant orange flowers against the green foliage were a showstopper" [syn: show-stopper, showstopper]