say it: MOWTH-fuul
mouthful is a noun meaning "the quantity that can be held in the mouth". It carries 2 recorded senses.
the quantity that can be held in the mouth
a small amount eaten or drunk
“take a taste--you'll like it”
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 mouthful come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.