A fantastic streak for Winter Olympian? (6)
I believe the answer is:
skater
'winter olympian?' is the definition.
(I've seen this in another clue)
'a fantastic streak' is the wordplay.
'a fantastic' is an anagram indicator (a fantastic or improbable ordering of the letters).
'streak' anagrammed gives 'SKATER'.
'for' is the link.
(Other definitions for skater that I've seen before include "Athlete on blades" , "Insect on pond - person on ice" , "Mover across ice" , "Streak (anag)" , "Performer on ice" .)