The English suffix "-ard" (as in "drunkard", "laggard", "braggard", and "sluggard") is used to make adjectives into deprecating nouns.
"He's drunk" is just a description.
"He's a drunkard" is a moral judgment that finds the subject lacking.
The same process turned "he's wise" into "he's a wizard".
"Wizard" was the medieval equivalent of "smartass".