Immoral umpire punished (6)

I believe the answer is:

impure

'immoral' is the definition.
(thesaurus)

'umpire punished' is the wordplay.
'punished' indicates an anagram.
'umpire' is an anagram of 'IMPURE'.

(Other definitions for impure that I've seen before include "Defiled" , "Sullied or adulterated" , "Lewd" , "Unclean" , "Dirty or immoral" .)

I've seen this clue in The Sun.

Want a hint initially instead of a full solution? Install my app