The constant one-upsmanship between the two siblings was tiresome.
one-upping
Frequency:
70
%
She was always one-upping her friends with her extravagant vacations.
one-upped
Frequency:
65
%
He felt one-upped by his rival's clever comeback during the debate.
Idiomatic Expressions for one-up
Phrase: one-up someone
Meaning: to outdo or surpass someone in a competitive or boastful manner
Usage: She always tries to one-up her sister by buying more expensive gifts.