An invention brought in by a foreigner (5)
I believe the answer is:
alien
'a foreigner' is the definition.
('alien' can be a synonym of 'foreigner')
'an invention brought in' is the wordplay.
'invention' becomes 'lie'.
'brought in' is an insertion indicator.
'an' enclosing 'lie' is 'ALIEN'.
'by' acts as a link.
(Other definitions for alien that I've seen before include "Foreign - film directed by Ridley Scott" , "Foreign (from outer space?)" , "Offensive" , "Being from another world" , "extraneous" .)