lous·y / ˈlouzē/ • adj. (lous·i·er, lous·i·est) 1. inf. very poor or bad; disgusting: the service is usually lousy lousy weather. ∎ ill; in poor physical condition: she felt lousy.2. infested with lice. ∎ (lousy with) inf. teeming with (something regarded as bad or undesirable): the town is lousy with tourists.DERIVATIVES: lous·i·ly / -zəlē/ adv.lous·i·ness n.