Small rebellion Greek character dismissed (4)
I believe the answer is:
tiny
'small' is the definition.
(similar in meaning)
'rebellion greek character dismissed' is the wordplay.
'rebellion' becomes 'mutiny' (mutiny is a kind of rebellion).
'greek character' becomes 'mu' (letter from the Greek alphabet).
'dismissed' is a deletion indicator.
'mutiny' with 'mu' taken out is 'TINY'.
(Other definitions for tiny that I've seen before include "Slight" , "Extremely small" , "Little" , "Microscopic" , "Quite insignificant" .)