lazydisapprovingHe's one of the laziest people I've ever met.
indolentSome of my classmates are indolent in their health habits.
slothfulliteraryTelevision and video games have bred a generation of slothful teens.
idleUKHe's an able student, just idle.
lethargicI felt very lethargic after such a big lunch.
shiftlessdisapprovingHe's so shiftless he'll never make it through school.
unambitiousWhat work she needs just seems to come to her. You'll never meet a more unambitious person in your life.
bone idleUKHe's so bone idle he won't even move from the couch.