Green’s Dictionary of Slang

a womanizer.

1603		Shakespeare Measure for Measure IV iii: All great doers in our trade.
1611		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.
1699		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.