The wife's endless deceit (4)
I believe the answer is:
frau
'the wife's' is the definition.
(Frau is an example)
'endless deceit' is the wordplay.
'endless' means to remove the last letter.
'deceit' becomes 'fraud' (fraud is a kind of deceit).
'fraud' with its last letter removed is 'FRAU'.
(Other definitions for frau that I've seen before include "German title for a woman" , "half of Hockenheimring?" , "German wife" , "German lady" , "German woman's title" .)