spare time; free time; leisure time
Refers to time when one is not occupied with work or duties; often used in contexts like doing something in one's spare time.
I write novels in my spare time.
I try to find free time to exercise.
side job; odd jobs; work done in one's spare time
Compound of 片手 (one hand) and 間 (interval, time), literally 'one-hand time', suggesting time when one is not fully occupied and can do something with one hand free.