Maggot
British SlangDefinition
A derogatory insult for a repulsive or contemptible person; archaically, a whimsical notion or stubborn fixation.
Examples
"After he grassed on his mates and stitched us up, the little maggot skulked off like nothing had happened."
"Don’t waste your breath arguing with that maggot at the pub—he thrives on being vile to everyone."
"He’s got a maggot in his head about moving to the coast and won’t stop banging on about seaside cottages."