say it: UHN-dur-wer
underwear is a noun meaning "undergarment worn next to the skin and under the outer garments". It carries one recorded sense.
undergarment worn next to the skin and under the outer garments
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 underwear 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.