Learn how to say Avengeful correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word avenge:
inflict harm in return for (an injury or wrong done to oneself or another):
he vowed in silent fervour to avenge their murders
inflict harm in return for an injury or wrong on behalf of (oneself or another):
we must avenge our dead
they avenged themselves on the interlopers
late Middle English: from Old French avengier, from a- (from Latin ad ‘to’) + vengier, from Latin vindicare ‘vindicate’