congratulate (v.)

"address with expressions of sympathetic pleasure," 1540s, from Latin congratulatus, past participle of congratulari "wish joy," from assimilated form of com "together, with" (see con-) + gratulari "give thanks, show joy," from gratus "agreeable" (from suffixed form of PIE root *gwere- (2) "to favor"). Related: Congratulated; congratulating; congratulable.