Quiz: Remember the definition of mal de mer?
1807, American English, "sauce, gravy, thick liquid," from Dutch doop "thick dipping sauce," from doopen "to dip" (cf. dip (v.)). Extension to "drug" is 1889, from practice of smoking semi-liquid opium preparation. Meaning "foolish, stupid person" is older (1851) and may have a sense of "thick-headed." Sense of "inside information" (1901) may come from knowing before the race which horse had been drugged to influence performance. Dope-fiend is attested from 1896.
1889, from dope (n.). Related: Doped; doping.
A narcotic, especially an addictive narcotic.
An illicit drug, especially marijuana.
[fr Dutch doop, ''sauce for dipping,'' with elaborate semantic shifts]