Consider this fictional situation which I made up to let you feel the sense:
Brad and Brett was chatting about recent thefts where cheats were making hoax and decieved the victims. While Brett was talking about a particular case of this kind of theft, Brad remembered he himself was duped in a similar way and almost went to tell Brett but swallowed his word thinking Brett might use this fact against him later in future to mock him.
So what is the word for the italicized phrase? I thought about "choke". But something tells me it isn't.
Best Answer
The idiomatic expression used for cases like that is bite your tongue, which means to stop yourself from saying something that might upset somebody or cause an argument, although you want to speak.
Choke could be used if you meant to be unable to speak normally especially because of strong emotion. It would not mean somebody avoided saying something he was going to say.