This is the 13075th most frequent German word.
abzulegen
"Abzulegen" means "to discard, take off (clothing), deposit, or file."
Here, 'abzulegen' means 'to take' an exam or test.
Er plant, die Prüfung nächste Woche abzulegen.
He plans to take the exam next week.
In this context, 'abzulegen' is used to mean 'to give up' or 'to shed' a habit.
Sie beschloss, ihre alte Gewohnheit abzulegen.
She decided to abandon her old habit.
Here, 'abzulegen' refers to 'shedding' or 'removing' something, in this case, the winter coat of animals.