pusher
1. A drug dealer or drug dealer's accomplice that approaches young teens and pressures them into taking free samples in order to get them addicted and coming back for more.

2. Anyone who tries to convince others to form a drug habit.
1. Hey, that man standing around the park just made John try some crack. Now he's gonna' by buying from him all the time.

2. Jake keeps telling me weed will solve all my problems. He's such a pusher.