Leader in revolt liable to be transported (4)
I believe the answer is:
rapt
'transported' is the definition.
(I've seen this before)
'leader in revolt liable' is the wordplay.
'leader in' says to take the initial letters.
'liable' becomes 'apt' ('apt' can be a synonym of 'liable').
The first letter of 'revolt' is 'r'.
'r'+'apt'='RAPT'
'to be' acts as a link.
(Other definitions for rapt that I've seen before include "Taken up entirely" , "Ecstatic - engrossed" , "carried away" , "Part (anag.)" , "Fascinated in part" .)