Wordnet 3.0
ADJECTIVE (1)
1. 
 lacking principles or scruples; 
- Example: "the rascally rabble"- Example: "the tyranny of a scoundrelly aristocracy" - W.M. Thackaray; 
- Example: "the captain was set adrift by his roguish crew"[syn: rascally, roguish, scoundrelly, blackguardly]
WordNet (r) 3.0 (2006):
scoundrelly
    adj 1: lacking principles or scruples; "the rascally rabble";
           "the tyranny of a scoundrelly aristocracy" - W.M.
           Thackaray; "the captain was set adrift by his roguish
           crew" [syn: rascally, roguish, scoundrelly,
           blackguardly]