runt
n. a small person; someone whose growth has been stunted. (Also a rude term of address.)He can't play basketball. He's just a runt.Hey, runt. Come here!
shrimp
n. a small person.Who's the little shrimp over by the door?I'm such a shrimp. I just have short genes.
spud
n. a short person. (Also a term of address.)He can jump pretty high for a spud.Hey, spud! I almost didn't see you!