In a way subject to challenge or worthy of debate.(adverb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "debatably" in a sentence
"But deciding that people from that country should be subjected to heightened scrutiny at our domestic checkpoints … that seems to fall into the arena of debatably reasonable policy."
"Mike Leigh's new play is called Grief – a stark choice of title that, debatably, gives away too much."
"But human qualities -- the characteristics that are debatably cultural or genetic -- are at least as unlikely as institutions to follow a path of stability interrupted by rapid evolution."