A course including day for lecture (8)
I believe the answer is:
admonish
'lecture' is the definition.
(thesaurus)
'a course including day' is the wordplay.
'course' becomes 'dish' (I've seen this before**).
'including' indicates putting letters inside.
'day' becomes 'mon'.
'dish' going around 'mon' is 'dmonish'.
'a'+'dmonish'='ADMONISH'
'for' acts as a link.
(Other definitions for admonish that I've seen before include "Forewarn" , "Reprove, warn" , "Warn sternly" , "Gently reprove" , "Chide or reprimand" .)