Hoax one out to become criminal (9)

I believe the answer is:
kidnapper
'criminal' is the definition.
(kidnapper is a kind of criminal)
'hoax one out to' is the wordplay.
'hoax' becomes 'kid'.
'one out to' becomes 'napper' (I can't explain this - if you can you should believe this answer much more).
'kid'+'napper'='KIDNAPPER'
'become' is the link.
Can you help me to learn more?
(Other definitions for kidnapper that I've seen before include "One who seizes" , "One wrongly takes" , "Captor of a human being, for ransom" , "serious offender" , "Paris, for example" .)
