dope

The story

1. Proto-Germanic · derived from*daupijaną
2. Frankish · derived from*daupijan
3. Old Dutch · derived from*dōpen
4. Middle Dutch · derived fromdopen
5. Dutch · derived fromdopen“to dip”
6. Dutch · borrowed fromdoop“thick dipping sauce”
7. English todaydope

From Dutch doop (“thick dipping sauce”), from Dutch dopen (“to dip”), from Middle Dutch dopen, from Old Dutch *dōpen, from Frankish *daupijan, from Proto-Germanic *daupijaną. “Doop” in the sense “narcotic drug” ultimately refers to viscous opium juice, the drug of choice of the ancient Greeks; “insider information” perhaps from knowing which horse had been doped in a race. Sense of "stupid person" perhaps following from the drug sense (i.e. relating to those intoxicated on opium), compare dope up. Related to English dip and German taufen. Unrelated to dopamine.

First known use, by meaning

• from late 19th c. An opiate, now particularly heroin.
• from early 20th c. Information, usually from an inside source, originally in horse racing and other sports.