Wiktionary
n. 1 (context vulgar English) A serious mistake. 2 (context vulgar pejorative English) One who continually makes mistakes. 3 (context vulgar pejorative English) An ineffective person.
WordNet
Usage examples of "fuckup".
Did you send me this butterfingered fuckup in order to teach me a lesson?
A two-man tail on Dick Stens, two men to swoop on his slightest probation fuckup.
I had been part of enough fuckups where friends had died because of insecure information.
We assumed it was a major fuckup, or else why would Graveline pull out so fast?
The only one Underhill had ever known had been a fellow grunt in Lieutenant Beevers's band of merry men, his real name being Philip Footler, but known everywhere as Phoorow, a sweet-faced young redneck who had participated in Lieutenant Beevers's second-greatest fuckup, a military exercise that took place in Dragon Valley, or down in Dragon Valley, as they used to say, them what was there.
In the general confusion and panic that gripped the battered nation over the following weeks, trivialities such as the Phu Lai fuckup were forgiven and forgotten.
Trying to lay the groundwork of a potentially big case without committing any of the procedural fuckups that would muddy the waters later on, for a third.