Duke is on track for conversation (9)
I believe the answer is:
discourse
'for conversation' is the definition.
(I've seen this before)
'duke is on track' is the wordplay.
'duke' becomes 'd' (abbreviation).
'on' says to put letters next to each other.
'track' becomes 'course' (synonyms).
'd'+'is'+'course'='DISCOURSE'
(Other definitions for discourse that I've seen before include "Formal discussion of a topic" , "Engage in conversation; debate" , "Communication verbally" , "Speech - conversation" , "To hold a conversation" .)