put one's foot in it v. phr.,
informal To speak carelessly and rudely; hurt another's feelings without intending to; make a rude mistake.
He put his foot in it with his remark about self-made men because Jones was one of them. She put her foot in her mouth with her joke about that church, not knowing that one of the guests belonged to it. [TahlilGaran] English Idioms Dictionary ▲