1.
mouth
The opening in the face used for eating and speaking.
He is a person who can keep secrets, so it's okay to tell him secrets.
口が堅い = tight-lipped
After running, my mouth gets dry and I get thirsty, so I drink a lot of water.
IDIOMATIC EXPRESSIONS:
- 口に合う: to suit one's taste
- 口が堅い: tight-lipped, discreet
- 口が軽い: loose-lipped, indiscreet
- 口を出す: to interfere, butt in
- 口を聞く: to speak, to mediate
EXTENDED MEANINGS:
口 also means "opening" and appears in many compound words:
- 入り口: entrance
- 出口: exit
- 窓口: service window, counter
- 改札口: ticket gate
Note: Reading changes to ぐち in compounds.