Let down blue deer variety (7)
I believe the answer is:
lowered
'let down' is the definition.
(I've seen this in another clue)
'blue deer variety' is the wordplay.
'blue' becomes 'low' (I've seen this in another clue).
'variety' indicates anagramming the letters.
'deer' is an anagram of 'ered'.
'low'+'ered'='LOWERED'
(Other definitions for lowered that I've seen before include "Threatened" , "looked sullen" , "Brought down" , "Moved downwards" , "Let down gently" .)