Dejected at being low on the list of actors (8)
I believe the answer is:
downcast
'dejected' is the definition.
(similar in meaning)
'being low on the list of actors' is the wordplay.
'being low' becomes 'down' ('down' is associated in meaning with 'low').
'on' says to put letters next to each other (in a down clue, letters appear on others).
'the list of actors' becomes 'cast' (I've seen this in another clue).
'down'+'cast'='DOWNCAST'
'at' is the link.
(Other definitions for downcast that I've seen before include "blue" , "Sad" , "Dispirited, gloomy" , "Crestfallen" , "Depressed - looking at the floor?" .)