Uneven; unconventional (9)
I believe the answer is:
irregular
I believe this clue is a double definition.
'uneven' is the first definition.
(similar in meaning)
'unconventional' is the second definition.
(similar in meaning)
(Other definitions for irregular that I've seen before include "Erratic" , "Unsymmetrical; soldier" , "Uneven - inappropriate" , "volunteer" , "Unconventional" .)