furtive
FUR-tivadjMeaning sly and secret, as if trying not to get caught
Memory hook FUR = THIEF: a sly, guilty look. The furry little thief tiptoes off with the fish, glancing back over its shoulder again and again; that sly, guilty look is furtive.
The raccoon cast a furtive look over its shoulder before diving into the trash can.
In context His furtive manner gave him away: he kept glancing at the door, hiding his hands in his pockets and jumping whenever anyone spoke.
Similar sneaky, sly, secretive, underhand
Opposite open, frank, forthright
From Latin furtivus, “stolen, secret,” from fur (thief).