pusher

One that pushes.

One who sells drugs illegally.

One who or that which pushes; one who drives forward.

In mech., a stem or rod, usually with a button on the outer end, by which, from the outside of an inclosed space, some movement or result is accomplished within the space by pressing upon the button or outer extremity of the rod to push it toward the interior.

One of the levers of a type-setting machine, which, when touched on the keyboard, dislodges and pushes out a type.