ingenuous (adj.) Look up ingenuous at Dictionary.com
1590s, "noble in nature," from Latin ingenuus "with the virtues of freeborn people, of noble character, frank, upright, candid," originally "native, freeborn," from in- "in" (see in- (2)) + gen-, root of gignere "beget, produce" (see genus). Sense of "artless, innocent" is 1670s, via evolution from "high-minded" to "honorably open, straightforward," to "innocently frank." Related: Ingenuously; ingenuousness.