louse /laʊs/noun 3verb 1forms 4phrases 3 noun3 •A small parasitic wingless insect of the order Psocodea. •(informal, old-fashioned) A contemptible person; one who is deceitful or causes harm.He said: "Thanks, friend; but you're wasting your time. You better warn Crocker. If that louse makes a play for me, he'll get hit with Chicago lightning!" — 1946 •(slang) The currency sign ¤. verb1 •To remove lice from; to delouse.‘Nor have I combed, washed or loused myself this six months past, there being so few daring deeds to do on this Highway.’ — 1936 formsloused · lousing · louses · lice Phrases with louse louse aroundTo slack off; to be lazy or a parasite on others. louse upTo mess up; to confuse; to put into a state of disorder. three skips of a louseThe worth of some trifling or insignificant matter; a whit or jot of value.