Nobleman meeting youth leader ahead of time (5)
I believe the answer is:
early
'ahead of time' is the definition.
(synonyms)
'nobleman meeting youth leader' is the wordplay.
'nobleman' becomes 'earl' (member of the nobility).
'meeting' means one lot of letters go next to another.
'youth leader' becomes 'y' (I've seen this in other clues).
'earl'+'y'='EARLY'
(Other definitions for early that I've seen before include "Opening" , "and 26: Too soon to be sure" , "Post this for Christmas?" , "Type of bird" , "near beginning" .)