足あしを滑すべらせる

expression, ichidan verb

lose one's footing; slip

Used literally for slipping on a surface, and figuratively for making a careless mistake or misstep.

• 雨あめの日ひは階かい段だんで足あしを滑すべらせやすい。

  On rainy days, it's easy to slip on the stairs.

• 大だい事じな試し合あいで足あしを滑すべらせてしまった。

  I made a crucial mistake in the important match.