Ready to fight for a fanciful dream (5)
I believe the answer is:
armed
'ready to fight' is the definition.
(I've seen this in another clue)
'a fanciful dream' is the wordplay.
'a fanciful' is an anagram indicator (a fanciful or silly ordering of the letters).
'dream' with letters rearranged gives 'ARMED'.
'for' acts as a link.
(Other definitions for armed that I've seen before include "Being equipped with 25 Across" , "Bearing weapons" , "prepared to shoot?" , "Equipped with weapons" , "ready to fight" .)