Compact needs to be settled (5)
I believe the answer is:
dense
'compact' is the definition.
(similar in meaning)
'needs to be settled' is the wordplay.
'to be settled' is an anagram indicator.
'needs' with letters rearranged gives 'DENSE'.
(Other definitions for dense that I've seen before include "Close-packed" , "Stupid, crowded together" , "Thick and tightly-packed" , "Maybe bovine" , "Closely-spaced" .)