OK for practising on (9)
I believe the answer is:
treatable
'ok' is the definition.
Both the definition and answer are adjectives.
Perhaps they are linked in a way I don't understand?
'practising on' is the wordplay.
I cannot quite understand how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'for' is the link.
Can you help me to learn more?
(Other definitions for treatable that I've seen before include "one can deal with" , "Can be handled" .)