to put one’s foot in one’s mouth (to put one’s foot in it)
idiom

- to unintentionally say something foolish, tactless, or offensive

The Free Dictionary

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WORD ORIGIN

The phrase “to put one’s foot in one’s mouth” dates from around 1900.

In the fight against unclear and bewildering application of the English language, British community activist Christie Maher launched the PLAIN ENGLISH CAMPAIGN (PEC) in 1979 by shredding hundreds of government forms in London’s Parliament Square.

In addition to its lobbying efforts, the PEC sponsors an annual "Foot In Mouth Award" for the most baffling quotes by public figures:

Here are some famous examples:

Former U.S. Secretary of Defense Donald Rumsfeld won the award in 2003 for this statement:

“Reports that say something hasn’t happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns — the ones we don’t know we don’t know.”

And here are a few other noteworthy foot-in-mouth moments:

California Governor Arnold Schwarzenegger: “I think that gay marriage is something that should be between a man and a woman.”

British super model Naomi Campbell: “I love England, especially the food. There’s nothing I like more than a lovely bowl of pasta.”

Hollywood actress Brooke Shields: “Smoking kills. If you’re killed, you’ve lost a very important part of your life.”

Former U.S. Vice President Dan Quayle: “If we don’t succeed, we run the risk of failure.”

Basketball star Shaquille O’Neal, when asked whether he visited the Parthenon during a trip to Greece: “I can’t really remember the names of the clubs that we went to.”

Trump On dating his daughter Ivanka: “I’ve said if Ivanka weren’t my daughter, perhaps I’d be dating her.”

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SMUGGLE OWAD into a conversation
say something like:

“John really PUT HIS FOOT IN HIS MOUTH during the interview.”