Dismal and ultimately dejected state (4)
I believe the answer is:
dark
'dismal' is the definition.
(I know that dismal can be written as dark)
'ultimately dejected state' is the wordplay.
'ultimately' suggests the final letters.
'state' becomes 'ark' (I've seen this before).
The last letter of 'dejected' is 'd'.
'd'+'ark'='DARK'
'and' acts as a link.
(Other definitions for dark that I've seen before include "Deprived of light" , "Gloomy" , "Such an unknown horse" , "Devoid of brightness" , "lacking lights" .)