The most common and most likely answer to this crossword clue is the 8 letter word GALLANTS
I've seen this crossword clue in The Times
G
A
L
L
A
N
T
S
More clues leading to the result GALLANTS
Buddy explains!

The straight part
We know that "Dashing youngsters" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dashing youngsters = gallants.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 GALLANTS mean?
GALLANTS noun- A fashionable young man who is polite and attentive to women.
- One who woos, a lover, a suitor, a seducer.
- Topgallant