Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
flightiness is a noun meaning "the trait of acting unpredictably and more from whim or caprice than from reason or judgment". It carries one recorded sense.
the trait of acting unpredictably and more from whim or caprice than from reason or judgment
“I despair at the flightiness and whimsicality of my memory”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for flightiness come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.