Leave out of room itself (4)
I believe the answer is:
omit
'leave out' is the definition.
(synonyms)
'of room itself' is the wordplay.
'of' says the answer is hidden in the clue.
'OMIT' can be found hidden inside 'room itself'.
(Other definitions for omit that I've seen before include "Leave out or overlook" , "Leave out or fail to do" , "Drop" , "Exclude; veto" , "Leave out, perhaps in error" .)