Justify women’s set finally touring Scottish island (7)
I believe the answer is:
warrant
'justify' is the definition.
(I know that warrant is a more specific form of justify)
'women's set finally touring scottish island' is the wordplay.
'women' becomes 'w' (standard abbreviation).
'finally' indicates one should take the final letters.
'touring' indicates putting letters inside (touring can mean going round).
'scottish island' becomes 'arran' (island off the coast of Scotland).
The final letter of 'set' is 't'.
'w'+'t'='wt'
'wt' enclosing 'arran' is 'WARRANT'.
(Other definitions for warrant that I've seen before include "Merit, justify" , "Travel pass" , "Permit for arrest, search of premises, etc" , "Guaranty - authorisation to make an arrest" , "Justify; authorisation" .)