A looser form of spray (7)
I believe the answer is:
aerosol
'spray' is the definition.
(as in an aerosol spray)
'a looser form' is the wordplay.
'form' indicates an anagram.
'looser' with letters rearranged gives 'erosol'.
'a'+'erosol'='AEROSOL'
'of' is the link.
(Other definitions for aerosol that I've seen before include "Spray creator" , "Container with device for releasing contents as fine spray" , "Air spray" , "What makes mist" , "A suspension" .)