Memorial regarding defeat getting cut down (5)
I believe the answer is:
relic
'memorial' is the definition.
(object kept to remember a holy person)
'regarding defeat getting cut down' is the wordplay.
'regarding' becomes 're' ('re' means regarding or about).
'defeat' becomes 'lick' (lick can mean to beat or defeat).
'getting cut down' means to remove the last letter.
'lick' with its final letter taken off is 'lic'.
're'+'lic'='RELIC'
(Other definitions for relic that I've seen before include "Venerated memento" , "Item surviving from the past" , "Revered religious remnant" , "Fossil" , "Keepsake, of a saint say" .)