Chap back to see indifference (9)

I believe the answer is:

disregard

I'm a little stuck... Click here to teach me more about this clue!

'indifference' is the definition.
(thesaurus)

'chap back to see' is the wordplay.
'chap back' becomes 'dis' (I can't justify this - if you can you should believe this answer much more).
'to see' becomes 'regard' ('regard' can be a synonym of 'see').
'dis'+'regard'='DISREGARD'

Can you help me to learn more?

(Other definitions for disregard that I've seen before include "Push aside" , "Overlook - inattention" , "Neglect, ignore" .)

I've seen this clue in The Mirror and The Daily Express.

Want a hint initially instead of a full solution? Install my app