to the bitter end

US /tə ðə ˈbɪtər ɛnd/
UK /tə ðə ˈbɪtər ɛnd/
"to the bitter end" picture
1.

until a struggle or unpleasant experience is completely finished, despite difficulties or suffering

:
•
They fought to the bitter end, refusing to surrender.
•
She decided to stick with the project to the bitter end, even though it was very challenging.
:
bitterbitternessbitter orangeendendingin the enda bitter pill (to swallow)