Only men go in at such a meeting (8)
I believe the answer is:
abutment
'a meeting' is the definition.
(I've seen this before)
'only men go in at' is the wordplay.
'only' becomes 'but' (but can mean only - eg 'life is but a dream').
'go in' is an insertion indicator.
'but'+'men'='butmen'
'butmen' put into 'at' is 'ABUTMENT'.
'such' acts as a link.
(Other definitions for abutment that I've seen before include "structural support" , "Meeting" , "Arch-supporting structure" , "Structure supporting an arch" .)