Meaning of Put your foot in your mouth
To say or do something that offends, upsets or embarrasses someone else.
The thing you said (or did) usually gets you into trouble, especially if you hadn’t thought carefully before speaking or doing it.
You embarrass yourself by saying something wrong or inappropriate, something that you should not have said openly.
Sometimes it can be an insensitive or tactless remark that you later regret saying.
Occasionally you didn’t realize that other people were listening to what you were saying and they may have found your comment or remark offensive or embarrassing.
In the end, whatever you said has caused an embarrassing or awkward situation.
You can also use this idiom when someone else does this. For example: