Frank? He's not involved (6)
I believe the answer is:
honest
'frank?' is the definition.
('honest' can be similar in meaning to 'frank')
'he's not involved' is the wordplay.
'involved' indicates an anagram (involved can mean confusing or complex).
'hes'+'not'='hesnot'
'hesnot' with letters rearranged gives 'HONEST'.
(Other definitions for honest that I've seen before include "Free of deceit, truthful by nature" , "Virtuous" , "Not cheating, just" , "Without dissimulation or guile" , "Trustworthy or candid" .)