くち すべらせる
kuchio suberaseru

Ichidan Verb
Expression

1. to make a slip of the tongue; to say something inadvertently; to blurt out without thinking

うっかり くち すべらせると おもわぬ結果 けっか まねくことが おうい。
ukkari kuchio suberaseruto omowanu kekkao maneku kotoga ōi.
A slip of the tongue often brings about unexpected results.
Other forms: