shellac (n.) Look up shellac at Dictionary.com
1713, from shell (n.) + lac (see lacquer). Translates French laque en écailles "lac in thin plates."
shellac (v.) Look up shellac at Dictionary.com
1876, from shellack (n.). The slang sense of "beat soundly" is 1920s, perhaps from the notion of shellac as a "finish." Shellacked "drunk" is from 1922 (compare plastered). Related: Shellacking.