Sparing space within rocky inlet (7)
I believe the answer is:
lenient
'sparing' is the definition.
(thesaurus)
'space within rocky inlet' is the wordplay.
'space' becomes 'en'.
'within' means one lot of letters goes inside another.
'rocky' indicates an anagram.
'inlet' with letters rearranged gives 'lenit'.
'en' put inside 'lenit' is 'LENIENT'.
(Other definitions for lenient that I've seen before include "Tolerant, rather than strict" , "Forgiving, soft" , "Merciful or easygoing" , "Inclined to let people off lightly" , "Light" .)