Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
headful is a noun meaning "the quantity of information that a head will hold". It carries 2 recorded senses.
the quantity of information that a head will hold
“he has a headful of baseball statistics”
a covering over the surface of your head
“a headful of tight curls”
“a headful of lice”
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 headful come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.