Students initially notice head's misery (7)
I believe the answer is:
sadness
'misery' is the definition.
(thesaurus)
'students initially notice head's' is the wordplay.
'initially' says to take the initial letters.
'notice' becomes 'ad'.
'head' becomes 'ness' (ness is a headland**).
The first letter of 'students' is 's'.
's'+'ad'+'ness'='SADNESS'
(Other definitions for sadness that I've seen before include "blues" , "Despondency" , "Gloom" , "Depression" , "Dejection" .)