Note about ill-bred puritans (6)
I believe the answer is:
prudes
'puritans' is the definition.
('prude' can be a synonym of 'puritan')
'note about ill-bred' is the wordplay.
'note' becomes 'ps' (PS is an example**).
'about' indicates putting letters inside.
'ill-bred' becomes 'rude' ('rude' can be a synonym of 'ill-bred').
'ps' placed around 'rude' is 'PRUDES'.
(Other definitions for prudes that I've seen before include "They are easily shocked by matters relating to sex" , "Persons of exaggerated propriety, too easily shocked" , "They're excessively concerned about propriety and decorum" , "People with exaggerated sense of propriety" , "Stuffy types" .)