■ noun
1》 informal an illegal drug, especially cannabis or ( US ) heroin.
↘a drug used to enhance the performance of an athlete, racehorse, or greyhound.
2》 informal a stupid person.
3》 informal information.
4》 a varnish formerly used to strengthen the fabric surface of aircraft.
5》 a lubricant.
■ verb
1》 administer ~ to (a racehorse, greyhound, or athlete).
↘( be ~d up ) informal be heavily under the influence of drugs.
2》 cover with varnish or other thick liquid.
3》 Electronics add an impurity to (a semiconductor) to produce a desired electrical characteristic.
4》 ( ~ something out ) informal, dated work something out.
■ adjective black slang very good.
Derivatives
~r noun
Origin
C19 (in the sense 'thick liquid'): from Du. doop 'sauce', from doopen 'to dip, mix'.