The most common and most likely answer to this crossword clue is the 8 letter word UPSTARTS
I've seen this crossword clue in The Daily Telegraph
U
P
S
T
A
R
T
S
More clues leading to the result UPSTARTS
- The nouveaux riches on horseback getting over jumps
- Johnny-come-latelies stumped in high-class roles
- Social climbers at college have quiche during the weekend
- Newcomers having successes with pastries
- Nouveau-riche people at university — with introductions
- Sour puss going off about rich nobodies
- American obtains celebrity through training egotistic new kids on the block
- State begins gathering social climbers
- Doctor puts on liberal studies for nouveaux riches
- Parvenus reconstituted start-ups
Buddy explains!

The straight part
We know that "Nouveau-riche people" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case nouveau-riche people = upstarts.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 UPSTARTS mean?
UPSTARTS verb- To rise suddenly, to spring