Emily Dickinson Lexicon

OAF, n. [said to be a corruption of ouph or elf, a fairy or demon, and to denote a foolish child left by fairies in the place of one of better intellects which they steal. Johnson.]

1. A changeling; a foolish child left by fairies in the place of another. Drayton.
2. A dolt; an idiot; a blockhead.