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