パンツ

パンツ is a loanword from English 'pants' with two distinct meanings in Japanese.

USAGE (sense 1, underwear):
When used alone, パンツ most commonly means underpants/underwear in everyday speech.

• パンツを履(は)く: to put on underwear
• パンツを洗(あら)う: to wash underwear
• 下着(したぎ)のパンツ: underwear

USAGE (sense 2, trousers):
In fashion contexts, パンツ refers to outer garments (trousers).

• ロングパンツ: long pants, trousers
• ショートパンツ: shorts
• 半(はん)パン: shorts (casual abbreviation)
• スキニーパンツ: skinny pants
• ジーンズ/ジーパン: jeans

Similar words

• 下着(したぎ): underwear (general term)
• ブリーフ: briefs
• トランクス: boxer shorts
• ズボン: trousers (the everyday word; from French jupon)
• スラックス: slacks, dress pants

Usage

Context usually makes the meaning clear. Fashion magazines and stores use パンツ for trousers, while in daily conversation it typically means underwear.