shellac (n.)
also shell lac, 1713, from shell (n.) + lac. Translates French laque en écailles "lac in thin plates." Commercially, lac was considered as stick lac (still on the twigs, insects and all), seed-lac (resin without the twigs and insects, partly processed), and fully processed plates of shell lac.
shellac (v.)
1876, from shellac (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.