louse (someone or something) up
To ruin, spoil, mess up, or bungle someone or something. Her sudden decision to quit in the middle of the project really loused us up. I am not letting your crummy attitude louse up my vacation—if you want to be grouch, you can go somewhere else and do it alone!
louse someone or something up
Inf. to ruin something; to mess someone or something up. You really loused me up! You got me in a real mess! Who loused up my scheme?
louse up
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.
louse up
v. To cause something to fail because of poor handling; botch something: The president loused up the merger, costing the company millions of dollars. Let me tell the story—you always louse it up.
louse something up
tv. to botch something up. Please don’t louse the typewriter ribbon up this time.