The most common and most likely answer to this crossword clue is the 9 letter word DEFEATIST
I've seen this crossword clue in The Daily Telegraph
D
E
F
E
A
T
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T
More clues leading to the result DEFEATIST
- Fed up, having worry, one good soul having negative attitude
- Clever — when full of worry is inclined to give up
- Feed poorly, at first being hopeless
- Journalist withdrawn before amazing action — it’s terrible he’s resigned
- Pessimistic sort of believer hiding accomplishment
- Negativist freethinker without accomplishment
- If teased badly, time to be despondent
- One with no hope of French act winning
Buddy explains!

The straight part
We know that "Pessimistic sort" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pessimistic sort = defeatist.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 DEFEATIST mean?
DEFEATIST noun- Someone who advocates defeatism, or has such an attitude
- Of, or relating to defeatism