noun
piece of cake; cinch; easy task
Colloquial expression meaning something is very easy to do. Often used in the phrase お茶の子さいさいだ to dismiss a task as trivial.
See also: お茶の子
こんな仕事、お茶の子さいさいだよ。
This kind of work is a piece of cake.
彼にとっては、その問題はお茶の子さいさいだった。
For him, that problem was a cinch.