Endless chat is chap's charm (8)
I believe the answer is:
talisman
'charm' is the definition.
(I've seen this before)
'endless chat is chap's' is the wordplay.
'endless' means to remove the last letter.
'chat' becomes 'talk' (I've seen this before).
'chap' becomes 'man' (I've seen this before).
'talk' with its final letter taken off is 'tal'.
'tal'+'is'+'man'='TALISMAN'
(Other definitions for talisman that I've seen before include "It's said to be a protection against evil" , "Object supposed to guard against evil" , "Object believed to have magical powers" , "Amulet" , "Object thought to guard against evil" .)