an animal that is small or stunted as compared with others of its kind.

the smallest or weakest of a litter, esp. of pigs or puppies.

a person who is small and contemptible

That runt causes most of the trouble at the meetings.

British Dialect .

an old or decayed tree stump.

an old cow or ox.

an ugly old woman; hag.

noun

half-pint , homunculus , lilliputian , midget , peewee * , punk * , shrimp * , dwarf , peewee , pygmy , shrimp