What's the difference between contentious and dissentious?

Contentious

Definition:

(a.) Fond of contention; given to angry debate; provoking dispute or contention; quarrelsome.
(a.) Relating to contention or strife; involving or characterized by contention.
(a.) Contested; litigated; litigious; having power to decide controversy.

Example Sentences:

(1) Republicans remain wary of a contentious debate on the divisive issue, which could anger their core voters and undercut potential electoral gains in the November elections when control of Congress will be at stake.
(2) How to administer the fund is another contentious area.
(3) They make a big deal when it happens, and then they forget.” The use of sarin has been highly contentious throughout the Syrian war.
(4) The election in the capital of the world’s largest Muslim-majority nation has been deeply contentious.
(5) I can only say, we want to do more in terms of research and we obviously want to support our scientists.” NCRIS is not specifically mentioned in the contentious higher education bill that the Senate will debate next week.
(6) I’ve never had a black person or a brown person ever say anything bad about me.” Then he proceeded to make fresh contentious comments, first by repeating the comparison between slavery and welfare dependence: “Receiving welfare and housing – is that a sense of slavery when you get caught up in that and can’t get out of it for generations?
(7) Garcia, who sought to interview all 22 executive committee members who made the contentious decision to award the 2018 World Cup to Russia and the 2022 tournament to Qatar but found some who are no longer in football beyond his reach, delivered his report this month.
(8) The Jedwabne massacre and Kaminski's line that "Jews should say sorry for killing Poles" during the second world war is by far the most important of the many contentious issues on this man.
(9) Samuel Wurzelbacher, who became famous during the 2008 election as “Joe the Plumber” after he had a heated discussion with Obama on the campaign trail, was championed by presidential nominee John McCain but later made contentious remarks such as a call to “put a damn fence on the border going to Mexico and start shooting”.
(10) Southern said on Tuesday it would reinstate travel passes for staff and allow them to swap shifts, reversing two contentious moves following strike action.
(11) Meanwhile, MPs in Athens approved the contentious reforms and austerity package demanded by its creditors amid angry scenes in parliament and violent clashes on the streets on Wednesday.
(12) Italy’s president, Giorgio Napolitano, has resigned, formally setting off what will be a contentious election to replace him.
(13) There is a growing conviction that medical technologies are major contributors to escalating costs, and regulating them is generally viewed as the least contentious way to control expenses in the 1980's.
(14) The contentious position is set to be waved into the final EU negotiating position by consensus.
(15) But this later proved contentious because the reserve appeared to preclude any resettlement of the atolls by islanders whose families had been evicted in 1965 to make way for a giant US air force base.
(16) The treasurer Joe Hockey has hinted the government might be prepared to shift ground on its insistence that a crucial $150m research funding extension hinges on the passage of contentious legislation to deregulate university fees.
(17) Business rates have long been a contentious issue among retailers, who argue the system penalises high street premises and unfairly benefits online retailers.
(18) Osborne also envisages “demonstrating the concept” of safe fracking by “focusing on a small number of sites in less contentious locations” including “public sector land (particularly MOD owned)”.
(19) Trump is an isolationist so the Chinese are going to see that as an opportunity to keep strengthening their position and their role in the region.” Delury said Trump was also likely to ditch the highly contentious Trans-Pacific Partnership (TPP) which under Obama had been “a centrepiece of an American resurgence of its role in Asia”.
(20) Political distortion And in all of this, Brooks consistently injected a highly contentious political ideology into the arteries of public debate, a toxic cocktail of crude populism and intellectual confusion.