Extraterrestrial finds fib in article (5)
I believe the answer is:
alien
'extraterrestrial' is the definition.
(synonyms)
'fib in article' is the wordplay.
'fib' becomes 'lie' (a fib is a lie).
'in' is an insertion indicator.
'article' becomes 'an' (indefinite article).
'lie' going into 'an' is 'ALIEN'.
'finds' acts as a link.
(Other definitions for alien that I've seen before include "ET" , "exciting film based in space" , "immigrant" , "Foreign - film directed by Ridley Scott" , "Belonging to a foreign country" .)