Dreadful things done without leader giving commands (10)
I believe the answer is:
directions
'commands' is the definition.
(direction is a kind of command)
'dreadful things done without leader' is the wordplay.
'dreadful' becomes 'dire' ('dire' can be a synonym of 'dreadful').
'things done' becomes 'actions' (I've seen this before).
'without leader' means to remove the first letter.
'actions' with its first letter removed is 'ctions'.
'dire'+'ctions'='DIRECTIONS'
'giving' acts as a link.
(Other definitions for directions that I've seen before include "North, south, east and west?" , "News reveals four" .)