Definition from Wiktionary, the free dictionary
one-upmanship (plural one-upmanships)
- (idiomatic) The art or practice of successively outdoing a competitor.
- They are bent on one-upmanship. I think it's hopeless to try to stop them.
- He always engaged in one-upmanship.
- (idiomatic) A succession of instances of outdoing a competitor.
art or practice of outdoing an opponent