Put in post before protest, a teacher goes round lost in thought (6-6)
I believe the answer is:
absent-minded
'lost in thought' is the definition.
(thesaurus)
'put in post before protest a teacher goes round' is the wordplay.
'put in post' becomes 'sent' (sent via the post).
'before' means one lot of letters go next to another.
'protest' becomes 'mind' (I can't explain this - if you can you should believe this answer much more).
'teacher' becomes 'BEd' (Bachelor of Education).
'goes round' means one lot of letters goes inside another.
'a'+'bed'='abed'
'sent'+'mind'='sentmind'
'sentmind' going within 'abed' is 'ABSENT-MINDED'.
Can you help me to learn more?
(Other definitions for absent-minded that I've seen before include "Forgetful, inattentive" , "Preoccupied U forgetful" , "Liable to inattentiveness" , "Wandering" , "Vague and forgetful" .)