1590s in a literal sense, agent noun from push (v.). Meaning "peddler of illegal drugs" (1935 in prison slang) is from the verb in the "promote" sense.
权威例句
1. When a drug pusher offered the Los Angeles youngster $100 to peddle drugs, Jack refused.
一个毒贩给杰克100美元让他贩卖毒品时,这个洛杉矶少年拒绝了。
2. Early on 14 November Ely Curtiss's pusher biplane was hoisted aboard.
十一月十四日晨,伊利的柯蒂斯推进式双翼机被吊上船.
3. Not only am I an addict, I am also a pusher.
我不仅是个瘾君子, 还是个推动者.
4. We have been waging a desperate campaign against the drug pusher.
我们已经发起一场运动,与贩毒分子作殊死斗争.
5. The notorious drug - pusher has been contriving an escape from the prison.