oaf

noun

1. a clumsy, stupid person; lout.
2. a simpleton; dunce; blockhead.
3. Archaic.
   1. a deformed or mentally deficient child.
   2. a changeling.

noun

1. a stupid or loutish person

n.1620s, auf, oph (modern form from 1630s), “a changeling; a foolish child left by the fairies” [Johnson], from a Scandinavian source, cf. Norwegian alfr “silly person,” in Old Norse, “elf” (see elf). Hence, “a misbegotten, deformed idiot.” Until recently, some dictionaries still gave the plural as oaves.