Teaches nonsense if ideas only partly recalled (7)
I believe the answer is:
edifies
'teaches' is the definition.
(edifying is a kind of teaching)
'nonsense if ideas only partly recalled' is the wordplay.
'only partly' indicates the answer is hidden within the clue.
'recalled' is a reversal indicator.
'seifide' can be found hidden inside 'nonsense if ideas'.
'seifide' reversed gives 'EDIFIES'.
(Other definitions for edifies that I've seen before include "schools" , "Spiritually strengthens" , "Morally instructs" .)