Most important, holy person welcomes stranger (7)
I believe the answer is:
salient
'most important' is the definition.
(I've seen this before)
'holy person welcomes stranger' is the wordplay.
'holy person' becomes 'st' (short for saint).
'welcomes' is an insertion indicator (in sense of 'invites in').
'stranger' becomes 'alien' (synonyms).
'st' going around 'alien' is 'SALIENT'.
(Other definitions for salient that I've seen before include "Leaping (heraldry)" , "Prominent - in tales (anag)" , "Foremost" , "Conspicuous; pointing outwards" , "Prominent, striking" .)