US officer training is never over houses (6)
I believe the answer is:
ensign
'us officer' is the definition.
(rank in some US armed forces)
'training is never over houses' is the wordplay.
'houses' indicates the answer is hidden within the clue (part of the clue houses the answer).
'over' says the letters should be written backwards.
'ngisne' is hidden within 'training is never'.
'ngisne' back-to-front is 'ENSIGN'.
(Other definitions for ensign that I've seen before include "Flag; standard-bearer" , "Soldier who carries the Colours" , "Low-ranking naval officer" , "US naval rank" , "officer in the US navy" .)