Words that mean ''to inadvertently say something'' [duplicate]
Like when you're talking and inadvertently say something and then realize it.
Freudian Slip or Parapraxis - "an error in speech, memory, or physical action that occurs due to the interference of an unconscious subdued wish or internal train of thought"
Blunder - "to utter stupidly, confusedly, or thoughtlessly", "to make a stupid, careless, or thoughtless mistake in"
Misspeak - "to express (oneself) imperfectly or incorrectly"
Let it slip - "to say (something that one did not want to say) by mistake"
To give away, a dead giveaway - ex: 1) Whoops, I gave away the answer. 2) The look on his face was a dead giveaway
Divulge - "make known (private or sensitive information)"
Blurt Out - "to utter suddenly or inadvertently; divulge impulsively or unadvisedly"
These are all words that could be used in the manner you described, depending on the context. If you give us an example sentence we may be able to help you out further :)