noun
Refers to unscheduled time between activities, such as a gap in one's schedule or a short break.
空き時間にコーヒーを飲みに行きませんか。
Shall we go for a coffee during our free time?
今日は午後から空き時間ができた。
I got some free time this afternoon.
暇 is a more general word for free time or leisure, often implying a longer period of idleness. 空き時間 specifically refers to a gap or interval in a schedule.
余暇 is a formal term for leisure time, often used in contexts like hobbies or work-life balance. 空き時間 is more casual and refers to short, incidental free periods.
Compound of 空き (あき, 'empty, vacant') + 時間 (じかん, 'time').