The Collaborative International Dictionary
Thiefly
Thiefly \Thief"ly\, a. & adv.
Like a thief; thievish; thievishly. [Obs.]
--Chaucer.
Wiktionary
thiefly
a. (context obsolete English) Like a thief; thievish. adv. (context obsolete English) Like a thief; thievishly.
Usage examples of "thiefly".
So, of course, he reflected wryly, here he was, bent on one last thiefly act.
It was a tight fit between the smooth flank and the hairy one, and it took all his thiefly skills to avoid a clink and rattle as he slid the coins into a smooth sweep of gleaming gold from end to end of the bed.
Some of these nobles sponsored or gave house room to apprentice mages, gaining the protection of thiefly fear of such guardians—to see him and raise the alarm .