Some deride a teacher … imagine (6)
I believe the answer is:
ideate
'imagine' is the definition.
(I know that imagine can be written as ideate)
'some deride a teacher' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'IDEATE' is hidden within 'deride a teacher'.
(Other definitions for ideate that I've seen before include "Imagine (psychology), aid tee (anag.)" , "Fancy" , "Form in the imagination" , "Form a picture of" .)