Forlorn nurse is drilling head (10)
I believe the answer is:
drearisome
'forlorn' is the definition.
Both the answer and definition are adjectives.
Perhaps there's a link between them I don't understand?
'nurse is drilling head' is the wordplay.
'nurse' becomes 'rear' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'drilling' is an insertion indicator (inserted letters drill through others).
'head' becomes 'dome' (dome can informally mean someone's head).
'rear'+'is'='rearis'
'rearis' put into 'dome' is 'DREARISOME'.
Can you help me to learn more?
(Other definitions for drearisome that I've seen before include "Lonely, desolate" , "Sad" .)