Agile duo involved in conversation (8)
I believe the answer is:
dialogue
'conversation' is the definition.
(dialogue is a kind of conversation)
'agile duo involved' is the wordplay.
'involved' indicates an anagram (involved can mean confusing or complex).
'agile'+'duo'='agileduo'
'agileduo' is an anagram of 'DIALOGUE'.
'in' is the link.
(Other definitions for dialogue that I've seen before include "Discussion" , "Talks" , "part of play one can't perform" , "brought into play perhaps" , "Agile duo in conversation" .)