The most common and most likely answer to this crossword clue is the 15 letter word EXISTENTIALISTS
E
X
I
S
T
E
N
T
I
A
L
I
S
T
S
More clues leading to the result EXISTENTIALISTS
Buddy explains!
The straight part
We know that "Jean-Paul Sartre and friends" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case jean-paul sartre and friends = existentialists.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 EXISTENTIALISTS mean?
EXISTENTIALISTS noun- A person who adheres to the philosophy of existentialism.