Former pupil learned note was wiped out (11)
I believe the answer is:
obliterated
'wiped out' is the definition.
('obliterate' can be a synonym of 'wipe out')
'former pupil learned note' is the wordplay.
'former pupil' becomes 'OB' (abbreviation for 'Old Boy' - private school pupil).
'learned' becomes 'literate' (able to read and write).
'note' becomes 'D' (musical note).
'ob'+'literate'+'d'='OBLITERATED'
'was' is the link.
(Other definitions for obliterated that I've seen before include "Erased" , "Effaced" , "Utterly destroyed" , "made hard to read" , "trashed" .)