Being very scared, became very hard (9)
I believe the answer is:
petrified
'hard' is the definition.
(similar in meaning)
'being very scared became very' is the wordplay.
I cannot really see how this works, but
'being' could be 'pet' (pet is a kind of being) and 'pet' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for petrified that I've seen before include "terror-stricken" , "scared stiff" , "Turned to stone - in extreme fear" , "Paralysed with fear" , "Frightened" .)