Definitions for muck up
botch, bodge, bumble, fumble, botch up, muff, blow, flub, screw up, ball up, spoil, muck up, bungle, fluff, bollix, bollix up, bollocks, bollocks up, bobble, mishandle, louse up, foul up, mess up, fuck up(verb)
make a mess of, destroy or ruin
"I botched the dinner and we had to eat out"; "the pianist screwed up the difficult passage in the second movement"
mire, muck, mud, muck up(verb)
soil with mud, muck, or mire
"The child mucked up his shirt while playing ball in the garden"
To ruin unintentionally.
To clown around; to have fun, often at the expense of others.