Dressed in a dreary outfit (7)
I believe the answer is:
arrayed
'dressed' is the definition.
(I've seen this in another clue)
'a dreary outfit' is the wordplay.
'a dreary' can be anagrammed to 'ARRAYED'.
Though, I am not sure how the anagram is indicated.
'in' is the link.
Can you help me to learn more?
(Other definitions for arrayed that I've seen before include "Formed up" , "Displayed in a particular way" , "Decoratively assembled" , "Ordered" , "Marshalled; (finely) dressed" .)