Prun"er (?), n.
One who prunes, or removes, what is superfluous.
Any one of several species of beetles whose larvae gnaw the branches of trees so as to cause them to fall, especially the American oak pruner (Asemum mestum), whose larva eats the pith of oak branches, and when mature gnaws a circular furrow on the inside nearly to the bark. When the branches fall each contains a pupa.
© Webster 1913.