Officer, low grade failure, shows how to kick horse, say (4,6)
I believe the answer is:
cold turkey
'kick horse say' is the definition.
The definition suggests a singular noun which matches the answer.
'officer low grade failure shows how' is the wordplay.
I cannot really see how this works, but
'officer' could be 'col' (short for colonel) and 'col' is found within the answer.
'failure' could be 'turkey' (turkey is a kind of failure) and 'turkey' is found within the answer.
A single letter 'd' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for cold turkey that I've seen before include "(Symptoms of) sudden withdrawal of addictive drug" , "taken in the days after Christmas?" , "Problems of withdrawal" , "Quick way to come off horse" , "result of stopping drugs" .)