It's legal, getting rid of leader — and nasty (5)
I believe the answer is:
awful
'nasty' is the definition.
(I know that nasty can be written as awful)
'it's legal getting rid of leader' is the wordplay.
'it's legal' becomes 'lawful' (associated in meaning).
'getting rid of leader' means to remove the first letter.
'lawful' with its first letter taken off is 'AWFUL'.
'and' acts as a link.
(Other definitions for awful that I've seen before include "rubbish" , "Appalling, terrible" , "Very embarrassing" , "Atrocious, dire" , "Dreadful, nasty" .)