cock-upˈcock-up noun [countable] British English spoken informal 
He’s made a monumental cock-up of his first assignment.cock-up over There’s been a cock-up over the tickets for the football on Saturday.
THESAURUSa stupid mistake
a stupid mistake caused by not thinking carefully enough about what you are saying or doing, which could have serious results: · In a serious blunder by the hospital, two babies were sent home with the wrong parents.
an embarrassing and stupid mistake made in a social situation or in public: · a serious gaffe in her speech about immigration
British English a very bad mistake, especially one that shows you do not know something, and that often makes other people laugh: · Photographers should be careful of making classic howlers, such as having a tree grow out of your subject’s head.
British English informal a silly mistake when you are doing something – a very informal use: · They made a cock-up with the bill.· The government is anxious to avoid any more cock-ups.
COLLOCATIONS FROM THE ENTRY He’s made a monumental cock-up of his first assignment.
something that has been spoiled by someone’s stupid mistake or by being done badly: He’s made a monumental cock-up of his first assignment. He’s made a monumental cock-up of his first assignment.cock-up over There’s been a cock-up over the tickets for the football on Saturday.