We should have a different term for this. "Dunk" requires rim contact. Call it a "throw-down", because that's literally what it is. Edit: Or, going off of Websters above-- maybe we should say "dunk" is the general term for a throw down, and a "slam dunk" requires physical hand-to-rim contact. Yes, I'll go with that.
A slam dunk, also simply known as dunk, is a type of basketball shot that is performed when a player jumps in the air, controls the ball above the horizontal plane of the rim, and scores by shoving the ball directly through the basket with one or both hands.[1] It is a type of field goal that is worth two points. Such a shot was known as a "dunk shot"[1] until the term "slam dunk" was coined by former Los Angeles Lakers announcer Chick Hearn.[2]