Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
show-stopper is a noun meaning "an act so striking or impressive that the show must be delayed until the audience quiets down". It carries 2 recorded senses.
an act so striking or impressive that the show must be delayed until the audience quiets down
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”
Definitions, synonyms and semantic relations for show-stopper come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.