noun

1. any thick liquid or pasty substance, or other material, used to lubricate or absorb something
2. 1. a dressing, varnish, or filler, as for protecting the cloth covering of airplane wings, surfaces, etc.
   2. any additive, as a food preservative
3. a drug used to stimulate or hinder a racehorse's performance
4. Informal any drug or narcotic, or such drugs collectively
5. Informal a slow-witted, stupid, or lethargic person
6. Slang
   1. advance information on a racehorse's condition
   2. any information, esp. as used for prediction
7. Slang a carbonated drink, usually cola
8. Photog. a developer

Etymology: Du doop, sauce, dip, baptism < doopen, to dip < Gmc *dup-, to be deep: see dimple

transitive verb doped, doping dop′·ing

1. to give dope to; treat with dope
2. to drug or stupefy
3. to introduce an adulterant, additive, or impurity into (another substance) in order to produce a deliberate change