Big order of lager (5)
I believe the answer is:
large
'big' is the definition.
(I know that big can be written as large)
'order of lager' is the wordplay.
'order of' indicates an anagram.
'lager' is an anagram of 'LARGE'.
(Other definitions for large that I've seen before include "Little's late partner" , "Great being regal" , "Copious" , "Regal (anag)" , "At which criminals possibly are free" .)