Clear the room up finally - tidy on both sides (5)
I believe the answer is:
empty
'clear' is the definition.
(thesaurus)
'the room up finally tidy on both sides' is the wordplay.
'finally' indicates one should take the final letters.
'on both sides' means to remove the middle letters (the left and right sides of the word are used).
'tidy' with its middle removed is 'ty'.
The last letters of 'the room up' are 'emp'.
'emp'+'ty'='EMPTY'
(Other definitions for empty that I've seen before include "Evacuate" , "Loneliness parents feel when their children leave home" , "Arabic quarter" , "'. . . . . vessels make the most sound'" , "Unoccupied" .)