a glutton for punishment
someone who seems to enjoy working hard or doing something unpleasant

[TahlilGaran] Dictionary of Contemporary English ▲

glutton for punishment
[humorous]
someone who seems to like working hard or doing things that most people would find unpleasant.
So as well as a full-time job and a family to look after, she's started taking an evening class. She's a glutton for punishment, that woman.

[TahlilGaran] English Idioms Dictionary ▲

glutton for punishment
a person who likes difficult or unpleasant tasks
My friend is a glutton for punishment and he will always do the most difficult jobs available.

[TahlilGaran] English Idioms Dictionary ▲

glutton for punishment
n. phr. A greedy person; someone who wants too much of something, such as food or drink, which will make him sick.
Fred eats so much red meat that he is a regular glutton for punishment.

[TahlilGaran] English Idioms Dictionary ▲