Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
self-assured is an adjective meaning "showing poise and confidence in your own worth". It carries one recorded sense.
showing poise and confidence in your own worth
“hardly more than a boy but firm-knit and self-confident”
Definitions, synonyms and semantic relations for self-assured come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.