Style of beer knocked back at noon (4)
I believe the answer is:
elan
'style' is the definition.
(I know that style can be written as elan)
'beer knocked back at noon' is the wordplay.
'beer' becomes 'ale' (type of beer).
'knocked back' says the letters should be written in reverse.
'at' is a charade indicator (letters next to each other).
'noon' becomes 'n' (abbreviation for noon).
'ale' backwards is 'ela'.
'ela'+'n'='ELAN'
'of' acts as a link.
(Other definitions for elan that I've seen before include "spirit" , "Bounce" , "Impetuosity - style" , "Vivacity, panache" , "Dash, style" .)