oft, many a time and
very often, with great frequency
1H4 I.ii.50 [Falstaff to Prince Hal, of the Hostess] thou hast called her to a reckoning many a time and oft
JC I.i.37 [Marullus to commoners] Many a time and oft / Have you climbed up to walls and battlements
MV I.iii.103 [Shylock to Antonio] many a time and oft / In the Rialto you have rated me / About my moneys and my usances