Quiet girl upset one married traveller (7)
I believe the answer is:
pilgrim
'traveller' is the definition.
(pilgrim is a kind of traveller)
'quiet girl upset one married' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'upset' indicates anagramming the letters.
'one' becomes 'i' (Roman numeral).
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'girl' is an anagram of 'ilgr'.
'p'+'ilgr'+'i'+'m'='PILGRIM'
(Other definitions for pilgrim that I've seen before include "One travelling to a sacred place" , "made progress, as booked" , "Traveller to a holy place" , "Christian, say" , "One journeying to holy place" .)