english
1
general::
Phrase(s): muck something up to ruin something. • I should never have trusted Jim with the repair work. He was bound to muck it up. • I asked her to take over for me while I was gone, and she really mucked it up. • She mucked up the whole deal.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Bungle, damage, make a mess of, as in Don't let him write the review; he's sure to muck it up. This idiom alludes to the verb muck in the sense of "spread manure on." [Early 1900s] For a synonym, see FOUL UP.
American Heritage Idioms