Satisfaction from one wearing strange raincoat gift (13)
I believe the answer is:
gratification
'satisfaction' is the definition.
(I know that satisfaction can be written as gratification)
'one wearing strange raincoat gift' is the wordplay.
'one' becomes 'I' (Roman numeral).
'wearing' means one lot of letters goes inside another.
'strange' is an anagram indicator.
'raincoat'+'gift'='raincoatgift'
'raincoatgift' with letters rearranged gives 'gratfication'.
'i' put inside 'gratfication' is 'GRATIFICATION'.
'from' acts as a link.
(Other definitions for gratification that I've seen before include "Source of pleasure" , "Delight" , "Feeling of satisfaction" , "giving pleasure" .)