Old style of loose red coat (3,4)
I believe the answer is:
art deco
'old style' is the definition.
(I've seen this before)
'loose red coat' is the wordplay.
'loose' indicates an anagram (letters are loosened from their original positions).
'red'+'coat'='redcoat'
'redcoat' is an anagram of 'ART DECO'.
'of' is the link.
(Other definitions for art deco that I've seen before include "Highly geometric style" , "Visual design style - redcoat (anag)" , "1920s and 1930s ornamental style" , "Nineteen twenty's and thirties style" , "Early C 20 style" .)