Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
illegitimately is an adverb meaning "in a manner disapproved or not allowed by custom". It carries 2 recorded senses.
in a manner disapproved or not allowed by custom
“He acted illegitimately when he increased the rent fourfold”
of biological parents not married to each other
“this child was born illegitimately”
Definitions, synonyms and semantic relations for illegitimately come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.