Frank's couple of auxiliary verbs
I believe the answer is:
candid
'frank's' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for candid that I've seen before include "Open and truthful" , "Truthful and straightforward" , "Frank - open" , "Frank, forthright" , "Forthrightly sincere" .)