Room for small cape to whirl (5)
I believe the answer is:
space
'room' is the definition.
(thesaurus)
'small cape to whirl' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'to whirl' indicates anagramming the letters.
'cape' anagrammed gives 'pace'.
's'+'pace'='SPACE'
'for' acts as a link.
(Other definitions for space that I've seen before include "Interstellar region" , "Expanse" , "Interstellar vacuum" , "sci-fi theme" , "-- Capsule; -- bar" .)