Wonderful king who wanders around with a rod? (7)
I believe the answer is:
diviner
'who wanders around with a rod?' is the definition.
(someone using a divining rod)
'wonderful king' is the wordplay.
'wonderful' becomes 'divine' (both can mean excellent).
'king' becomes 'R' (abbreviation for rex, king in Latin).
'divine'+'r'='DIVINER'
(Other definitions for diviner that I've seen before include "More sacred" , "He finds water" , "even more delightful" , "one conjectures" , "Expert at finding liquid assets" .)