Antiquated perjorative, but etymology interesting.
Dastard (Page: 367)
Das"tard (?), n. [Prob. from Icel. dæstr exhausted. breathless, p. p. of dæsa to groan, lose one's breath; cf. dasask to become exhausted, and E. daze.] One who meanly shrinks from danger; an arrant coward; a poltroon.

You are all recreants and dashtards, and delight to live in slavery to the nobility. Shak.

and a usual suspect in a mellerdrammer...

"Dastardly Dick"...

and wasn't there a cartoon...?

Dastardly Dan-- i think,lending evidence to my feble mind i am losing it! -