From The Collaborative International Dictionary of English v.0.48 :
Thinly \Thin"ly\, a. In a thin manner; in a loose, scattered manner; scantily; not thickly; as, ground thinly planted with trees; a country thinly inhabited. [1913 Webster]From WordNet (r) 3.0 (2006) :
thinly adv 1: without force or sincere effort; "smiled thinly" 2: without viscosity; "the blood was flowing thin" [syn: thinly, thin] [ant: thick, thickly] 3: in a small quantity or extent; "spread the margarine thinly over the meat"; "apply paint lightly" [syn: thinly, lightly] [ant: thickly] 4: in a widely distributed manner; "thinly overgrown mountainside" [ant: densely, thickly]