noun
outsmarting oneself; too clever for one's own good
Refers to a situation where one's own cleverness or excessive thinking backfires, leading to a worse outcome. Often used when someone overthinks and ends up making a mistake.
あれこれ考えすぎて、知恵負けしてしまった。
I thought too much and ended up outsmarting myself.
彼は知恵負けして、簡単な問題を間違えた。
He was too clever for his own good and got a simple question wrong.
裏目に出る means a plan backfires, which can be a result of 知恵負け, but 知恵負け specifically involves one's own cleverness as the cause.
Compound of 知恵 (wisdom, cleverness) and 負け (losing, being defeated). The exact historical derivation is uncertain, but the meaning is transparent from the components.