Prominent foreigner seen in street (7)
I believe the answer is:
salient
'prominent' is the definition.
('salient' can be a synonym of 'prominent')
'foreigner seen in street' is the wordplay.
'foreigner' becomes 'alien' ('alien' can be a synonym of 'foreigner').
'seen in' is an insertion indicator.
'street' becomes 'st'.
'alien' put into 'st' is 'SALIENT'.
(Other definitions for salient that I've seen before include "Prominent - in tales (anag)" , "defence work" , "Outstanding - it's lean (anag)" , "Prominent, striking" , "Leaping (heraldry)" .)