undershorts

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++un·der·shorts /ˈʌndəʃɔːts $ ˈʌndərʃɔːrts/ noun [plural]  underpants for men or boys 〔男用〕短裤，内裤

Examples from the Corpus

undershorts• The body of Nichols when found was clad only in undershorts.• Lately, the foundation has cashed in on sales of undershorts.• A few grams can be legitimately shed by stripping to undershorts and T - shirts.• He was wearing undershorts, he remembered that.

un·der·shorts nounChineseSyllable  

Corpus boys men or for underpants

undershorts
un‧der‧shorts /ˈʌndəʃɔːts $ ˈʌndərʃɔːrts/ noun [plural]
underpants for men or boys

under·shortsBrE /ˈʌndəʃɔːts/ 🔊NAmE /ˈʌndərʃɔːrts/ 🔊 noun [plural] (NAmE) underpants that are worn by men （男用）内裤，衬裤