Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
once-over is a noun meaning "a swift cursory examination or inspection". It carries one recorded sense.
a swift cursory examination or inspection
“I gave him the once-over”
Definitions, synonyms and semantic relations for once-over come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.