Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
showstopper 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”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for showstopper come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.