Unruly teens seen in a state (9)
I believe the answer is:
tennessee
'a state' is the definition.
(Tennessee is an example)
'unruly teens seen' is the wordplay.
'unruly' indicates an anagram.
'teens'+'seen'='teensseen'
'teensseen' anagrammed gives 'TENNESSEE'.
'in' is the link.
(Other definitions for tennessee that I've seen before include "US state, capital Nashville" , "American state, capital Nashville" , "Famous American playwright . . . . . . . . . Williams" , "Volunteer State" , "State of south-east US" .)