ingrate (n.) Look up ingrate at Dictionary.com
"ungrateful person," 1670s, from earlier adjective meaning "unfriendly," also "ungrateful, unthankful" (14c.), from Latin ingratus "unpleasant, disagreeable," also "ungrateful, unthankful," and "thankless, unprofitable," from in- "not" (see in- (1)) + gratus "pleasing, beloved, dear, agreeable" (from suffixed form of PIE root *gwere- (2) "to favor").