Tough outside but somewhat easier indoors (4)
I believe the answer is:
rind
'tough outside' is the definition.
'rind' can be an answer for 'outside' (I've seen this before). I am not certain of the 'tough' bit.
'somewhat easier indoors' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'RIND' can be found hidden inside 'easier indoors'.
'but' is the link.
Can you help me to learn more?
(Other definitions for rind that I've seen before include "Skin of bacon" , "Cheese or fruit skin" , "outside" , "Skin of orange or melon" , "Outer layer (of cheese)" .)