Most odd gent going out with stars (9)
I believe the answer is:
strangest
'most odd' is the definition.
(the most strange or most odd)
'gent going out with stars' is the wordplay.
'going out with' indicates an anagram (out can mean wrong or inaccurate).
'gent' with its letters mixed up with 'stars' makes 'STRANGEST'.
(Other definitions for strangest that I've seen before include "Most unusual or odd" , "Most unusual, oddest" , "Most out of the ordinary and unexpected" , "Most peculiar" , "Most remarkable" .)