grooming excuse 

Any use of a feeble, or implausible excuse used by someone to escape from a conversation on a mind-numbing, or uninteresting topic for the listener. Refers to someone explaining their preference to 'wash their hair', 'do their nails' or some other such excuse, which would be an otherwise less desirable chore than having to suffer through listening to such a boring conversation.

These excuses were popular in sit-coms, where the lead actor wanted to extract laughter from the audience with the punchline illustrating the implausibility of the excuse being believed by the recipient.

Claire: When I came back with your wine you'd already left. What happened?

Steve: When that wine-snob came over to talk about the wine we were drinking, I had to use a grooming excuse to get out of there.

grooming excuse by WineBusProf February 20, 2015