from Wiktionary, Creative Commons Attribution/Share-Alike License
- adv. In a thievish manner; like a thief.
from The Century Dictionary and Cyclopedia
- In a thievish manner; like a thief; by theft.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adv. in a manner characteristic of a thief
thievish + -ly (Wiktionary)