Cool shade keeps chap cold inside (8)
I believe the answer is:
inhumane
'cold inside' is the definition.
'cool shade keeps chap' is the wordplay.
'cool' becomes 'in' (I've seen this in other clues).
'shade' becomes 'hue' (I've seen this before).
'keeps' means one lot of letters goes inside another.
'chap' becomes 'man' (I've seen this before).
'hue' enclosing 'man' is 'humane'.
'in'+'humane'='INHUMANE'
(Other definitions for inhumane that I've seen before include "Not compassionate" , "Heartless" , "Cruel" , "Callous" .)