Shown in lesson, e.g., lecturer's lack of care (7)
I believe the answer is:
neglect
'lack of care' is the definition.
(I've seen this before)
'shown in lesson e g lecturer's' is the wordplay.
'shown in' indicates the answer is hidden within the clue.
'NEGLECT' is hidden within 'lesson e g lecturers'.
(Other definitions for neglect that I've seen before include "Failure to give proper care" , "Fail to attend to properly, task or person" , "Treat carelessly" , "Let slide" , "Fail to act or take care" .)