involving or likely to cause controversy; "a central and contentious element of the book"- Tim W.Ferfuson
inclined or showing an inclination to dispute or disagree, even to engage in law suits; "a style described as abrasive and contentious"; "a disputatious lawyer"; "a litigious and acrimonious spirit"
overlapping in duration; "concurrently with the conference an exhibition of things associated with Rutherford was held"; "going to school and holding a job at the same time"