Mean, spiteful (5)
I believe the answer is:
nasty
I believe this is a double definition.
'mean' is the first definition.
(similar in meaning)
'spiteful' is the second definition.
(similar in meaning)
(Other definitions for nasty that I've seen before include "Horrible" , "One who sees the future" , "Foul" , "grave" , "Not nice" .)