Likely, reasonable (9)
I believe the answer is:
plausible
I believe this clue is a double definition.
'likely' is the first definition.
(synonyms)
'reasonable' is the second definition.
(I've seen this before)
(Other definitions for plausible that I've seen before include "False but sounding true" , "likely" , "Apparently reasonable or probable" , "Credible" , "Seemingly true" .)