| kuài | rapid/quick/speed/rate/soon/shortly/quick-witted/clever/sharp (of knives or wits)/forthright/plain-spoken/gratified/pleased/pleasant/police runner (in former times, official to arrest criminals) |
| 快 | rapid quick speed |
| 快中子 | fast neutrons |
| 快乐 | happy merry |
| 快乐丸 | [Medicine] MDMA (3, 4-Methylenedioxymethamphetamine); ecstasy (a psychoactive drug possessing stimulant and hallucinogenic properties) |
| 快乐原则 | pleasure principle; principle of pleasure |
| 快乐幸福 | cheerful happy |
| 快乐的 | joyous; merry; hedonic; gladsome; delectable; chirrupy; good-humored; lighthearted; festival; joyful; happy; pleasurable; delighted; landmark; jolly; pleasant; sunny; gayest; gayer; carnivalesque; cheery; felicitous; good-humoured |
| 快乐说 | [Philosophy] hedonics |
| 快书 | clapper ballad |
| 快事 | satisfaction |
| 快人 | straightforward man |
| 快人快语 | straight talk from a straight person |
| 快件 | express mail |
| 快信 | letter by express mail |
| 快凝水泥 | fast-setting cement |
| 快刀斩乱麻 | lit. quick sword cuts through tangled hemp (idiom); decisive action in a complex situation cutting the Gordian knot |
| 快刀断乱麻 | lit. quick sword cuts through tangled hemp (idiom); decisive action in a complex situation cutting the Gordian knot |
| 快可立 | Quickly, tapioca milk tea franchise |
| 快嘴 | one who is quick to express his idea; a long tongue; quicktongued |
| 快婿 | good son-in-law |