Men giddily at the edge in wild revel (4)
I believe the answer is:
orgy
'wild revel' is the definition.
(I've seen this before)
'men giddily at the edge' is the wordplay.
'men' becomes 'OR' (military abbreviation for Other Ranks).
'at the edge' says to hollow out the word (remove centre letters) (I've seen 'at the edges' mean this).
'giddily' with its centre taken out is 'gy'.
'or'+'gy'='ORGY'
'in' acts as a link.
(Other definitions for orgy that I've seen before include "Licentious revel" , "Bacchanal" , "Riotous revel" , "Bacchanalian party" , "Debauched party" .)