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"
not meeting requirements; "unequal to the demands put upon him"
(followed by `of') lacking capacity or ability; "incapable of carrying a tune"; "he is incapable of understanding the matter"; "incapable of doing the work"
(followed by `of') not having the temperament or inclination for; "simply incapable of lying"
lacking the necessary skill or knowledge etc.; "an incapable helper"