Union official (9)
'union official' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for shop steward that I've seen before include "Union official" , "Unionist" , "One who's organizing hands" , "Workers' representative" , "Workplace representative of unionised employees" .)
(Other definitions for organiser that I've seen before include "Co-ordinator" , "Manager" , "Runner" , "One managing" , "storage container" .)