Vacuous

In tree work,you rise through the ranks by starting off as a 'ground man'(an empty headed vacuous lout).As you gain knowledge,you work your way through the alphabet from 'D'
man-all the way up to 'A'(a super duper tree man).On paper,an 'A' man should be able to do everything.But very few men ever reach every stage of 'A'-ness.In fact,you can be an 'A',in say,knot tying,but still a 'B' or 'C' in saw cutting.Few trimmers ever become an all out-flow blown 'A'man' in every aspect of their game.