Small notice over head brings sorrow (7)
I believe the answer is:
sadness
'sorrow' is the definition.
('sadness' can be a synonym of 'sorrow')
'small notice over head' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'notice' becomes 'ad'.
'over' is a charade indicator (letters next to each other).
'head' becomes 'ness' (ness is a headland**).
's'+'ad'+'ness'='SADNESS'
'brings' acts as a link.
(Other definitions for sadness that I've seen before include "Melancholy" , "Unhappy feeling" , "Sorrowful quality" , "Gloom" , "Misery" .)