doorknob

A circular device attached to a door, the rotation of which permits the unlatching of the door.

A doorknob of whatever roundish shape is effectively a continuum of levers, with the axis of the latching mechanism—known as the spindle—being the fulcrum about which the turning takes place.

A stupid person.

(especially psychiatry) To suddenly bring up a time-consuming topic when very little time remains to discuss it, often as a tactic to avoid conversation.