Note pocketed by sweet little thing needing no deciphering (2,5)
I believe the answer is:
en clair
'no deciphering' is the definition.
I can't tell whether this defines the answer.
'note pocketed by sweet little thing' is the wordplay.
'note' becomes 'c' (musical note).
'pocketed by' means one lot of letters goes inside another.
'sweet little thing' becomes 'enlair' (I can't explain this - if you can you should believe this answer much more).
'c' put within 'enlair' is 'EN CLAIR'.
'needing' is the link.
Can you help me to learn more?
(Other definitions for en clair that I've seen before include "in common parlance" , "in plain language" , "not coded" , "in understandable form" , "Put straightforwardly" .)