promiscuous; loose; unfaithful
Derogatory term for a person, especially a woman, who is sexually promiscuous or unfaithful. Often used in a judgmental or insulting way.
There's a rumor going around that she's promiscuous.
That guy is unfaithful; he quickly makes a move on other women.
Describes a person who is light on their feet, quick to act, or lively. Can be used positively or neutrally, unlike the first sense.
He's quick and gets his work done fast.
That kid is so energetic, he dashes off in no time.
Implies acting without thinking, being impulsive or hasty. Often carries a negative connotation of recklessness.
I failed because of a rash decision.
His thoughtless remark caused trouble.
promiscuous woman; loose woman
Compound of 尻 (buttocks) and 軽 (light). The original meaning likely referred to being light on one's feet, which extended metaphorically to being quick to act, and later to being sexually loose. The exact historical derivation is uncertain.