louse up

[louse up] {v.}, {slang} To throw into confusion; make a mess of;spoil; ruin.

When the man who was considering John's house heardthat the basement was wet, that was enough to louse up the sale.

Fred's failure in business not only lost him his business but lousedhim up with his wife.

The rain loused up the picnic.

See: MESSUP(2), FUCK UP.