Meaning

• To make a mistake, to go wrong.

  "You really fucked up this time."

• To botch or make a mess of.

  "I fucked up question 3 of the exam."

• To injure or damage badly.

  "I fucked up my knee while running the marathon."

• To cause someone to make a big mistake.

• (used only in imperative) Short for shut up.

  "Fuck up, mate! I don't want to listen to you!"

Meaning

• A serious mistake.

  "Forgetting our anniversary was a major fuckup."

• One who continually makes mistakes.

  "You've got to fire that fuckup."

• An ineffective person; a person who fucks up a lot

  "Don't mind me, I'm just a harmless fuckup."