Blunder or mistake (UK slang)

गलती

English Usage: That was a real bollocks up in the project.

Hindi Usage: वह परियोजना में एक असली गलती थी।

Testicles (slang, often used in a vulgar context)

To mess something up

बिगाड़ना

English Usage: He really bollocked up that presentation.

Hindi Usage: उसने वास्तव में उस प्रस्तुति को बिगाड़ दिया।

To scold or reprimand