Uneasy setter’s supporting others (7)
I believe the answer is:
restive
'uneasy' is the definition.
(synonyms)
'setter's supporting others' is the wordplay.
'setter's' becomes 'ive' ('I've', referring to the crossword setter).
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'others' becomes 'rest' (eg the rest of a group).
'ive' put after 'rest' is 'RESTIVE'.
(Other definitions for restive that I've seen before include "It veers around, resisting control" , "Uneasy, nervous" , "Fidgety, uneasy" , "Unable to keep still" , "Impatient - jumpy" .)