Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
guiltily is an adverb meaning "in the manner of someone who has committed an offense". It carries one recorded sense.
in the manner of someone who has committed an offense
“she blushed guiltily as she spoke”
Definitions, synonyms and semantic relations for guiltily come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.