Observes absence of publication for teachers? (5)
I believe the answer is:
notes
'observes' is the definition.
('note' can be a synonym of 'observe')
'absence of publication for teachers?' is the wordplay.
'absence of' becomes 'no'.
'publication for teachers?' becomes 'tes' (Times Educational Supplement).
'no'+'tes'='NOTES'
(Other definitions for notes that I've seen before include "Memos; marks" , "output from musicians" , "registers?" , "fivers?" , "Paper money" .)