Bollocks up is a slang term that refers to making a mess or creating a big mistake. A synonym for bollocks up could be to botch, meaning to ruin something or to fail at a task. Another synonym for bollocks up could be to bungle, which refers to making a mess or to handle something clumsily. To flub is also a synonym for bollocks up; this term refers to making a mistake or an error when performing a task. To mishandle or to mismanage can also be used as a synonym for bollocks up, which means to handle something incompetently or without skill.