Keen-eyed one seeing golfer's achievement (5)
I believe the answer is:
eagle
This could be a double definition.
'keen-eyed one' is the first definition.
(I've seen this in another clue)
'golfer's achievement' is the second definition.
'eagle' can be an answer for 'achievement' (thesaurus). I'm not certain of the 'golfer's' bit.
'seeing' acts as a link.
Can you help me to learn more?
(Other definitions for eagle that I've seen before include "Bird of prey; former children's comic" , "Bird with hooked bill and long broad wings" , "Large birds of prey." , "Former US coin" , "The emblem of the US is bald" .)