Revolutionary leaders on an island synonymous with a large land mass (4)
I believe the answer is:
asia
'large land mass' is the definition.
(I've seen this in another clue)
'revolutionary leaders on an island synonymous with a' is the wordplay.
'revolutionary' is a reversal indicator.
'leaders on' says to take the initial letters.
'with' means one lot of letters go next to another.
The initial letters of 'an island synonymous' is 'ais'.
'ais'+'a'='aisa'
'aisa' written backwards gives 'ASIA'.
(Other definitions for asia that I've seen before include "Put out" , "Earth's largest continent" , "The nations of the East, collectively" , "Populous continent" , "space for economic expansion?" .)