1 [uncountable and countable]BE
when you officially announce that you have decided to leave your job or an organization, or a written statement that says you will be leaving [↪ notice]:
The governor refused to accept Cox's resignation.
hand in/tender your resignation (=officially say that you want to resign)
when someone calmly accepts a situation that cannot be changed, even though it is bad:
She gave a sigh of resignation.
He accepted her decision with resignation.