A proverb meaning that petty people, when idle, are likely to do bad or malicious things — an admonition about idleness leading to mischief.
小人閑居して不善をなすと言うが、暇なときほど自分を律する必要がある。
They say an idle person is likely to do evil; the more free time you have, the more you need to discipline yourself.
SNSで悪口を書き込む人を見て、まさに小人閑居して不善をなすだと感じた。
Seeing people post abusive comments on social media, I felt it's exactly a case of idle people doing bad things.
地域で若者が退屈して問題を起こすのは、小人閑居して不善をなすの典型だ。
Young people in the community causing trouble out of boredom is a typical example of 'idle people doing evil.'