Adoptee supposedly lucky to miss first course (5)
I believe the answer is:
ascot
'course' is the definition.
(Ascot is a racecourse)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for ascot that I've seen before include "Where the Queen often sees racehorses" , "Racing to the strange coast" , "track" , "prestigious meeting" , "English racecourse in Berkshire" .)