Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
re-emphasise is a verb meaning "emphasize anew". It carries one recorded sense.
emphasize anew
“The director re-emphasized the need for greater productivity”
Definitions, synonyms and semantic relations for re-emphasise come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.