c. 1400, "natural transient small dent in some soft part of the human body," especially that produced in the cheek of a young person by the act of smiling, perhaps from an Old English as a word meaning "pothole," perhaps ultimately from Proto-Germanic *dumpilaz, which has yielded words in other languages meaning "small pit, little pool" (such as German Tümpel "pool," Middle Low German dümpelen, Dutch dompelen "to plunge").
In place-names from c. 1200; as a surname from late 13c. Meaning "slight indentation or impression in any surface" is from 1630s. Related: Dimples.
1570s (implied in dimpled), intransitive, "form dimples," from dimple (n.). Transitive sense "mark with dimples" is from c. 1600.