
ins Fettnäpfchen treten
to put one's foot in it
To make a clumsy, tactless, or embarrassing remark or action without intending to. This is by far the most common use of the word.
Als ich sie nach ihrem Mann fragte, trat ich voll ins Fettnäpfchen, denn sie waren frisch geschieden.
When I asked her about her husband, I really put my foot in it, because they had just gotten divorced.
