The most common and most likely answer to this crossword clue is the 11 letter word ADOLESCENTS
I've seen this crossword clue in The Daily Telegraph
A
D
O
L
E
S
C
E
N
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S
More clues leading to the result ADOLESCENTS
Buddy explains!

The straight part
We know that "Young people" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case young people = adolescents.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ADOLESCENTS mean?
ADOLESCENTS noun- A person who is in adolescence; someone who has reached puberty but is not yet an adult.