changeling (n.) Look up changeling at
1550s, "one given to change," from change (n.) + diminutive suffix -ling. Meaning "person or thing left in place of one secretly taken" is from 1560s; specific reference to an infant or young child (usually stupid or ugly) supposedly left by the faeries in place of one they took is from 1580s. An earlier word for it was oaf or auf.