A barbed tongue noun phrase
If someone has a barbed tongue, they tend to criticize or speak in a way that hurts or upsets others.
How can a person with a barbed tongue like Mary be eligible enough to be a teacher?
My boss had made some very spiteful remarks to me several times, but yesterday I couldn't put up with his barbed tongue anymore and came back at him.
John is always making others upset because of his barbed tongue.
The origin of this phrase is not clear.
To tell someone the truth about something that they had not understood or received false information
I have to set my wife straight about what happened yesterday.