-ard

CIDE DICTIONARY

-ard,  

 The termination of many English words; as, coward, reynard, drunkard, mostly from the French, in which language this ending is of German origin, being orig. the same word as English hard. It usually has the sense of one who has to a high or excessive degree the quality expressed by the root; as, braggart, sluggard.  [1913 Webster]

OXFORD DICTIONARY

-ard, suffix.
1 forming nouns in depreciatory senses (drunkard; sluggard).
2 forming nouns in other senses (bollard; Spaniard; wizard).

Etymology

ME & OF f. G -hard hardy (in proper names)