This is the 233rd most frequent Polish word.
mógł
"Could" (past tense of "can").
Here, "mógł" is part of the conditional "mógłbyś," used for polite requests.
Mógłbyś mi pomóc z tym zadaniem?
Could you help me with this task?
In this case, "mógł" is in the past tense, expressing a possibility that was not realized.
On mógł pojechać na wakacje, ale wybrał pracę.
He could have gone on vacation, but he chose work.
Here, "mógł" is used in a conditional clause, expressing a hypothetical situation.