loon

nouns

a worthless lazy fellow
loon
is a type of (narrower)
person who does no work
"a lazy bum"
bum, do-nothing, idler, layabout, loafer
large somewhat primitive fish-eating diving bird of the northern hemisphere having webbed feet placed far back; related to the grebes
diver, loon
a person with confused ideas; incapable of serious thought
addle-head, addlehead, birdbrain, loon
is derived from
loony