Dope \Dope\, v. t.

1. To treat or affect with dope; as, to dope nitroglycerin; specif.:
   (a) To give stupefying drugs to; to drug. [Slang]
   (b) To administer a stimulant to (a horse) to increase his speed. It is a serious offense against the laws of racing. [Race-track Slang]

2. To judge or guess; to predict the result of, as by the aid of dope. [Slang]

Source: Webster's Revised Unabridged Dictionary (1913)
 

Dope \Dope\ (d[=o]p), n. [D. doop a dipping, fr. doopen to dip. Cf. Dip.]

1. Any thick liquid or pasty preparation, as of opium for medicinal purposes, of grease for a lubricant, etc.

2. Any preparation, as of opium, used to stupefy or, in the case of a race horse, to stimulate. [Slang or Cant]

3. An absorbent material; esp., in high explosives, the sawdust, infusorial earth, mica, etc., mixed with nitroglycerin to make a damp powder (dynamite, etc.) less dangerous to transport, and ordinarily explosive only by suitable fulminating caps.

4. Information concerning the previous performances of race horses, or other facts concerning them which may be of assistance in judging of their chances of winning future races; sometimes, similar information concerning other sports. [Sporting Slang]

Source: Webster's Revised Unabridged Dictionary (1913)