Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
undemonstrative is an adjective meaning "not given to open expression of emotion". It carries one recorded sense.
not given to open expression of emotion
Definitions, synonyms and semantic relations for undemonstrative come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.