Reticence of the writer penning poetry ending in neglect (7)
I believe the answer is:
modesty
'reticence' is the definition.
(thesaurus)
'the writer penning poetry ending in neglect' is the wordplay.
'the writer' becomes 'my' (I can't explain this - if you can you should give a lot more credence to this answer).
'penning' is an insertion indicator.
'poetry' becomes 'odes' (ode is a type of poem).
'ending in' suggests the final letters.
The final letter of 'neglect' is 't'.
'odes'+'t'='odest'
'my' placed around 'odest' is 'MODESTY'.
'of' is the link.
Can you help me to learn more?
(Other definitions for modesty that I've seen before include "Decorum, shyness" , "Quality of being unpretentious" , "Self-deprecating quality" , "Unassumingness" , "Reserve" .)