In a raincoat, Joe has charm (5)
I believe the answer is:
magic
'charm' is the definition.
(thesaurus)
'in a raincoat joe' is the wordplay.
'in' is an insertion indicator.
'a raincoat' becomes 'mac' (macintosh is a type of raincoat).
'joe' becomes 'GI' (GI Joe).
'mac' placed around 'gi' is 'MAGIC'.
'has' acts as a link.
(Other definitions for magic that I've seen before include "The art of illusion" , "Art that supposedly invokes supernatural powers" , "Wonderful" , "Tricks" , "Illusory feat" .)