Pessimistic (8)
'pessimistic' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for downbeat that I've seen before include "Understated; gloomy" , "Conductor is likely to make this movement" , "Gloomy; laid-back" , "Miserable; relaxed" , "gesture by conductor" .)
'pessimistic' is the definition.
(associated in meaning)
This is all the clue.
(Other definitions for negative that I've seen before include "Piece of photographic film" , "A test result" , "Opposite of affirmative" , "'Pessimistic, gloomy (8)'" , "This required for development" .)
'pessimistic' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for gloomy that I've seen before include "Dreary" , "Downcast" , "Sombre" , "Dark - pessimistic" , "'Morose, glum (6)'" .)