Tenth medical arranged (7)
I believe the answer is:
decimal
'tenth' is the definition.
(thesaurus)
'medical arranged' is the wordplay.
'arranged' indicates an anagram.
'medical' anagrammed gives 'DECIMAL'.
(Other definitions for decimal that I've seen before include "A point in maths" , "Claimed, wrongly, to have this currency" , "Claimed (anag) - a point" , "System based on 10" , "of Number Ten" .)