Gratify or gladden (6)
I believe the answer is:
please
This clue is a double definition.
'gratify' is the first definition.
(I know that please is a type of gratify)
'gladden' is the second definition.
(thesaurus)
(Other definitions for please that I've seen before include "Entertain" , "Polite word of request" , "Cause (someone) to feel satisfied" , "See 10 Across" , "Make happy or glad" .)