Efface ages first of epitaphs gives (5)
I believe the answer is:
erase
'efface' is the definition.
(I know that efface can be written as erase)
'ages first of epitaphs gives' is the wordplay.
'ages' becomes 'eras' (I've seen this before).
'first of epitaphs gives' becomes 'e' (I can't justify this - if you can you should give a lot more credence to this answer).
'eras'+'e'='ERASE'
(Other definitions for erase that I've seen before include "Destroy recording on audio or video tape" , "Put out of mind" , "Remove evidence of" , "Remove, wipe out" , "Kill" .)