To hang bending downward; to sink or hang down, as an animal, plant, etc., from physical inability or exhaustion, want of nourishment, or the like.

To proceed downward, or toward a close; to decline.

To let droop or sink.

Downward bending of the blades at rest, due to gravity.

droop, sink, or settle from or as if from pressure or loss of tautness

hang loosely or laxly; "His tongue lolled"

commonly refers to the dynamic motion of an iron head, the toe drooping, or bending, downward because of the velocity of the swing and the action of the shaft.

Nothing to do with Breweries! Droop is the amount the shaft is deflected in the toe down direction at impact.