This is the 13634th most frequent Polish word.
pobić
"To beat" or "to hit."
In this case, 'pobić' literally means to strike repeatedly as a method of cleaning or dusting off a surface, specifically with a carpet.
Musiałem pobić dywan, żeby pozbyć się kurzu.
I had to beat the carpet to remove the dust.
In this sentence, 'pobić' is used metaphorically to mean achieving a new personal best or surpassing a previous achievement.
On pobił swój rekord w biegu na 100 metrów.
He broke his record in the 100-meter run.
Here, 'pobić' reflects a physical conflict or altercation, used in a reflexive form 'pobiły się', denoting that the action is mutual among participants.