- The definition of a shit eating grin is a cocky or self satisfied smile, usually after a person got away with something.
An example of a shit eating grin is the smile a person has after everyone believed a lie he told.
Slang a sly, knowing, or self-satisfied grin: somewhat vulgar
(plural shit-eating grins)
- The term is ambiguous and may indicate either a genuine broad smile (e.g. smug happiness) or a fake broad smile (e.g. trying to hide or get away with something).