Discussion involving singular herb (7)
I believe the answer is:
parsley
'discussion involving singular herb' is the definition.
I can't judge whether this defines the answer.
'discussion involving singular herb' is the wordplay.
'discussion' becomes 'parley' (parley is a kind of discussion).
'involving' indicates putting letters inside.
'singular herb' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'parley' placed around 's' is 'PARSLEY'.
Can you help me to learn more?
(Other definitions for parsley that I've seen before include "Use the herb sparely" , "You might misuse this herb sparely" , "Herb with either flat or crinkly leaves" , "Herb for garnishing" , "Food-flavouring herb for players" .)