Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
slightingly is an adverb meaning "in a disparaging manner". It carries one recorded sense.
in a disparaging manner
“these mythological figures are described disparagingly as belonging `only to a story'”
Definitions, synonyms and semantic relations for slightingly come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.