brljati

1. colloq. to botch; to bungle; to mess up
   Nemoj da brljaš, uradi to kako treba. — Don't mess around, do it properly.
   Majstor je brljao danima i ništa nije popravio. — The repairman bungled around for days and fixed nothing.
2. colloq. (brljati po + loc.) to mess about in dirt; to splash in muck
   Deca su ceo dan brljala po blatu. — The kids were messing about in the mud all day.

The perfective zabrljati "to screw up" is very common.