Open or liable to objection or debate; objectionable or debatable.
derivatives
ex·ceṕtion·a·biĺi·ty
noun
ex·ceṕtion·a·bly
adverb
usage note
Usage Note: Exceptionable and exceptional are not interchangeable. Only exceptionable means “objectionable” or “debatable”; exceptional means “uncommon” or “extraordinary.”
The American Heritage® Dictionary of the English Language, Fourth Edition