Ranks as a ground state (8)
I believe the answer is:
arkansas
'state' is the definition.
(Arkansas is an example)
'ranks as a ground' is the wordplay.
'ground' indicates an anagram (grind the letters ).
'ranks'+'as'+'a'='ranksasa'
'ranksasa' is an anagram of 'ARKANSAS'.
(Other definitions for arkansas that I've seen before include "River joining Mississippi" , "South-eastern US state" , "used to be a Land of Opportunity" , "Birth state of Bill Clinton" , "Confederate state in the American Civil War" .)