Like a cat, boy with that many lives? (7)
I believe the answer is:
leonine
'like a cat' is the definition.
(I've seen this before)
'boy with that many lives?' is the wordplay.
'boy' becomes 'Leo' (boy's name).
'with' means one lot of letters go next to another.
'that many lives?' becomes 'nine' (I can't explain this - if you can you should believe this answer much more).
'leo'+'nine'='LEONINE'
Can you help me to learn more?
(Other definitions for leonine that I've seen before include "Description of pride" , "Lion-like" , "Resembling a lion" , "As a maned animal" , "Like a big cat" .)