US city in Oklahoma? Hardly (5)
I believe the answer is:
omaha
'us city' is the definition.
(I've seen this before)
'in oklahoma? hardly' is the wordplay.
'in' indicates a hidden word.
'OMAHA' is hidden in the letters of 'oklahoma hardly'.
(Other definitions for omaha that I've seen before include "O, a ham found in US city on Missouri river" , "US city; D-Day 16" , "- - Beach (WWII)" , "place in Nebraska" , "Cotton fabric used for curtains and upholstery" .)