The Collaborative International Dictionary of English v.0.48:
Dastardly \Das"tard*ly\, a. Meanly timid; cowardly; base; as, a dastardly outrage. [1913 Webster]WordNet (r) 3.0 (2006):
dastardly adj 1: despicably cowardly; "the unprovoked and dastardly attack by Japan on...December 7th"- F.D. Roosevelt [syn: dastard(a), dastardly]