Noun
(informal) A swollen ear resulting from a blow to the side of the head.
In the football game he got caught by someone's elbow and came away with a thick ear.
(informal, by extension, often in the phrase 'give someone a thick ear') A punishment or threatened punishment notionally taking the form of a blow around the head.
Say that again and I'll give you a thick ear.
I was cheeky to the Police Officer and got a thick ear for my trouble.