By alternating current assertion, editor becomes famous (9)
I believe the answer is:
acclaimed
'famous' is the definition.
(thesaurus)
'by alternating current assertion editor' is the wordplay.
'by' means one lot of letters go next to another.
'alternating current' becomes 'AC' (synonyms).
'assertion' becomes 'claim' (claim is a kind of assertion).
'editor' becomes 'ed' (abbreviation).
'ac' put next to 'claim' is 'acclaim'.
'acclaim'+'ed'='ACCLAIMED'
'becomes' is the link.
(Other definitions for acclaimed that I've seen before include "Hailed, heralded" , "Strongly praised" , "Highly respected" .)