Activity, fitness for strenuous exertion; always used in an obscene, or at least ambiguous sense: “doing is a., and he will still be doing,” H5 III, 7, 107 (cf. Do). “if she call your a. in question,” Troil. III, 2, 60. “that your a. may defeat and quell the source of all evil,” Tim. IV, 3, 163.