Colombia greeted traveller focused on sun (5)
I believe the answer is:
comet
'traveller focused on sun' is the definition.
(comets orbit the sun)
'colombia greeted' is the wordplay.
'colombia' becomes 'co'.
'greeted' becomes 'met' (meet can mean to greet or receive).
'co'+'met'='COMET'
(Other definitions for comet that I've seen before include "Frozen body" , "Orbiting extraterrestrial body" , "astronomical sight" , "traveller covering huge mileage" , "Tailed space traveller" .)