1) Capable of being debated 2) Contentious 3) Controversial 4) Debatable 5) Disputable 6) Doubtful 7) Dubious 8) Moot 9) Not quite self-evident 10) Open to argument or debate 11) Plausible 12) Questionable 13) Uncertain 14) Undecided 15) Undetermined 16) Unsettled 17) Up for debate 1) Controversial 2) Debatable 3) Moot 4) Plausible 
• (a.) Capable of being argued; admitting of debate.
Ar'gu·a·ble adjective Capable of being argued; admitting of debate. 
[adj] - capable of being supported by argument 2. [adj] - open to argument or debate
debatable adjective open to argument or debate; `that is a moot question`
susceptible to debate, challenge, or doubt; questionable: Whether this is the best plan of action or not is arguable. · susceptible to being supported by convincing or persuasive argument: Admirers agree that it is arguable he is the finest pianist of his generation.