noun
Refers to a feeling of comfort, satisfaction, or pleasantness. Often used in compounds like 快感 (pleasant sensation) or 快適 (comfortable).
温泉に入ると、心身ともに快を感じる。
When I soak in a hot spring, I feel pleasure both physically and mentally.
noun
rapid train (abbreviation)
Abbreviation of 快速 (rapid train). Used in train service names like 快特 (rapid limited express). Not used as a standalone word for 'rapid'.
「快特」の「快」は快速の略です。
The 快 in 快特 is an abbreviation of 快速 (rapid).