muddy up
/ˈmʌdi ʌp/◆phrasal verb
make something dirty or complicated
The kids muddied up the whole room with their toys and paint.
The children made a mess in the room with their toys and paint.
informal
to make something dirty, especially with mud
The kids muddied up the bathroom after playing outside.
The children made the bathroom dirty with mud after playing outside.
informal
to make a situation or issue more complicated or confused
The new policy muddied up the already complex issue.
The new policy made the already complex issue even more confusing.
English Dictionary