Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
pent-up is an adjective meaning "characterized by or showing the suppression of impulses or emotions". It carries one recorded sense.
characterized by or showing the suppression of impulses or emotions
“her severe upbringing had left her inhibited”
“a very inhibited young man, anxious and ill at ease”
“their reactions were partly the product of pent-up emotions”
“repressed rage turned his face scarlet”
Definitions, synonyms and semantic relations for pent-up come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.