He's Tony, formulating an advisable policy (7)
I believe the answer is:
honesty
'advisable policy' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'he's tony formulating' is the wordplay.
'formulating' indicates anagramming the letters.
'hes'+'tony'='hestony'
'hestony' with letters rearranged gives 'HONESTY'.
'an' acts as a link.
Can you help me to learn more?
(Other definitions for honesty that I've seen before include "Straightforwardness" , "Probity; plant" , "Integrity" , "that's easily cultivated" , "Candour" .)