Roast tuna cooked for distant traveller (9)
I believe the answer is:
astronaut
'distant traveller' is the definition.
'astronaut' can be an answer for 'traveller' (astronaut is a kind of traveller). I am not sure about the 'distant' bit.
'roast tuna cooked' is the wordplay.
'cooked' is an anagram indicator (letters cooked into a new form).
'roast'+'tuna'='roasttuna'
'roasttuna' is an anagram of 'ASTRONAUT'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for astronaut that I've seen before include "For member of high-flying mission" , "Person trained to travel in a spacecraft" , "Skier" , "High-flyer" , "Santa tour for space traveller" .)