Amusing retiring characters in small order (5)
I believe the answer is:
droll
'amusing' is the definition.
(thesaurus)
'retiring characters in small order' is the wordplay.
'retiring' says the letters should be written in reverse.
'characters in' indicates a hidden word.
'llord' is hidden within 'small order'.
'llord' reversed gives 'DROLL'.
(Other definitions for droll that I've seen before include "Strangely amusing" , "Whimsically comical" , "Comical in an odd or whimsical manner" , "Whimsical - amusing" , "Humorous or whimsical" .)