Cheap booze, no good, upset teacher (5)
I believe the answer is:
tutor
'teacher' is the definition.
(tutor is a kind of teacher)
'cheap booze no good upset' is the wordplay.
'cheap booze' becomes 'rotgut' (I've seen this before).
'no' indicates named letters should be taken away.
'good' becomes 'g' (abbreviation).
'upset' says the letters should be written backwards.
'rotgut' with 'g' taken out is 'rotut'.
'rotut' written backwards gives 'TUTOR'.
(Other definitions for tutor that I've seen before include "Edify" , "Individual teacher" , "Master" , "He shows us the way" , "Mentor" .)