louse up

1. Spoil, ruin, bungle. For example, The bad weather loused up our plans, or Your change of mind really loused me up. This slangy expression originated in World War I, when infestation with lice was the common lot of soldiers in the trenches; its figurative use dates from the 1930s.

Example Sentences

I didn’t want to louse up the photo opportunity because it was the only chance to get the picture we all wanted, Clinton and Assad.

From Washington Post

The winter storm bearing down on the region and most of the East Coast on Wednesday louses up plans for everyone but those who planned to sit at home in a rocker by the fireplace.

From Washington Post

In either instance, it louses up my request.

From Time

I’m aware of it, still don’t use it, and yet I’ve yet to lose or corrupt any data or louse up the file system of a storage device.

From Time

I said okay, I didn't want to louse up the deal over a little thing like that.

From Project Gutenberg