In ceremony, call notes of credit "iffy"... (7)
I believe the answer is:
dubious
'iffy' is the definition.
(thesaurus)
'in ceremony call notes of credit' is the wordplay.
I cannot really understand how this works, but
'call' could be 'dub' (both can mean to name) and 'dub' is found within the answer.
'notes' could be 'ious' (I Owe You notes) and 'ious' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for dubious that I've seen before include "Sceptical, doubtful" , "unreliable" , "Of questionable value" , "Doubtful, uncertain" , "Ambiguous or suspect" .)