First class beer regularly ignored (6)
I believe the answer is:
former
'first' is the definition.
(I know that former is a type of first)
'class beer regularly ignored' is the wordplay.
'class' becomes 'form' (synonyms).
'regularly ignored' means one should take alternating letters (letters removed at regular intervals).
The alternate letters of 'beer' are 'er'.
'form'+'er'='FORMER'
(Other definitions for former that I've seen before include "The first of two mentioned" , "Core for winding an electrical core" , "Past; first (of two)" , "Erstwhile" , "Ex-" .)