Evil one disheartened Lionel (3)
I believe the answer is:
ill
'evil' is the definition.
(I've seen this in other clues)
'one disheartened lionel' is the wordplay.
'one' becomes 'i' (Roman numeral).
'disheartened' says to hollow out the word (remove centre letters).
'lionel' with its centre removed is 'll'.
'i'+'ll'='ILL'
(Other definitions for ill that I've seen before include "state, briefly" , "Harmful" , "Green round the gills" , "Sickly" , "Unwell, sick" .)