Webster's Revised Unabridged Dictionary · 1913

Dastard

Dastard (das"tẽrd) , noun

[Probably from Icelandic dastr exhausted. breathless, past participle of dasa to groan, lose one's breath; compare dasask to become exhausted, and English 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. — Shakespeare

Dastard , adjective

Meanly shrinking from danger; cowardly; dastardly.
Their dastard souls. — Addison

Dastard , transitive verb

To dastardize. [Rare] — Dryden