Vision by prophet shows traveller (9)
I believe the answer is:
sightseer
'traveller' is the definition.
(sightseer is a kind of traveller)
'vision by prophet' is the wordplay.
'vision' becomes 'sight' (synonyms).
'by' means one lot of letters go next to another.
'prophet' becomes 'seer' (both can mean someone who tells the future).
'sight'+'seer'='SIGHTSEER'
'shows' is the link.
(Other definitions for sightseer that I've seen before include "Tourist visiting scenes of interest" , "Visitor to famous locations" , "Rubberneck" , "Tripper" .)