A bit hasty, mate shot nevertheless (2,4,2,2,3)
I believe the answer is:
be that as it may
'nevertheless' is the definition.
(I've seen this before)
'a bit hasty mate shot' is the wordplay.
'shot' indicates an anagram.
'a'+'bit'+'hasty'+'mate'='abithastymate'
'abithastymate' with letters rearranged gives 'BE THAT AS IT MAY'.
(Other definitions for be that as it may that I've seen before include "Meaty habitats (anag) - despite what you've just said" , "of no importance" , "In spite of that (2,4,2,2,3)" , "Nevertheless" .)