She's spiteful though less than scathing (3)
I believe the answer is:
cat
'she's spiteful' is the definition.
I can't judge whether this defines the answer.
'less than scathing' is the wordplay.
'less' indicates a hidden word (the clue less some of the letters in it).
'CAT' is hidden in the letters of 'than scathing'.
'though' acts as a link.
Can you help me to learn more?
(Other definitions for cat that I've seen before include "Moggy" , "eg Leopard" , "Tiger, for instance" , "Carnivore; whip" , "one's pyjamas? They're an excellent thing" .)