Man from Wales, lieutenant (6)
I believe the answer is:
leslie
'man' is the definition.
'from wales lieutenant' is the wordplay.
'from' indicates a hidden word.
'LESLIE' is hidden in the letters of 'wales lieutenant'.
(Other definitions for leslie that I've seen before include "I'll see (anag) - boy's name" , "- Howard, British actor (Gone with the Wind)" , "Long-running dispute" .)