From The Collaborative International Dictionary of English v.0.48 [gcide]: Ofttimes \Oft"times`\, adv. [Oft + time. Cf. -wards.] Frequently; often. --Milton. [1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
ofttimes
adv 1: many times at short intervals; "we often met over a cup
of coffee" [syn: frequently, often, oftentimes,
oft, ofttimes] [ant: infrequently, rarely,
seldom]