False as some boy's name (5)
I believe the answer is:
bogus
'false' is the definition.
(thesaurus)
'some boy's name' is the wordplay.
'some boy' becomes 'bo'.
'name' becomes 'gus' (**).
'bo'+'gus'='BOGUS'
'as' is the link.
(Other definitions for bogus that I've seen before include "Mock" , "Pretended" , "Not genuine, sham" , "that's not real" , "Sham, phoney" .)