Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
thigh-slapper is a noun meaning "a joke that seems extremely funny". It carries one recorded sense.
a joke that seems extremely funny
Definitions, synonyms and semantic relations for thigh-slapper come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.