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-assertion is a noun meaning "the act of putting forth your own opinions in a boastful or inconsiderate manner that implies you feel superior to others". It carries 2 recorded senses.
the act of putting forth your own opinions in a boastful or inconsiderate manner that implies you feel superior to others
the act of asserting yourself in an aggressive manner
Definitions, synonyms and semantic relations for self-assertion come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.