Ferret's origins (5)
I believe the answer is:
roots
'ferret's origins' is the definition.
'roots' can be an answer for 'origins' ('root' can be a synonym of 'origin'). I'm not sure about the 'ferret's' bit.
'ferret's origins' is the wordplay.
'ferret' becomes 'root' (as in rooting or ferreting around for something).
'origins' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'root'+'s'='ROOTS'
Can you help me to learn more?
(Other definitions for roots that I've seen before include "Antecedents" , "Sources, rummages" , "eg Parsnips" , "Underground parts of plants" , "one's ancestry" .)