Green’s Dictionary of Slang

doer n.1

[do v.1 (1a)]

a womanizer.

[UK]Shakespeare Measure for Measure IV iii: All great doers in our trade.
[UK]Davies of Hereford Scourge of Folly 93: Why then he lou’d a man and woman too; But lou’d them passing well that well could Doo. Go too then Lotus, sith you are a dooer.
D’Urfey Pills V 340: Now to you ye dry Wooers, / Old Beaus and no doers, / So doughty, so gouty / So useless and toothless, / You blinders, cold kindness, / Has nothing of Man.