The most common and most likely answer to this crossword clue is the 9 letter word DEJECTION
D
E
J
E
C
T
I
O
N
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The straight part
We know that "Unhappiness" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unhappiness = dejection.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 DEJECTION mean?
DEJECTION noun- A state of melancholy or depression; low spirits, the blues.
- The act of humbling or abasing oneself.
- A low condition; weakness; inability.
- Defecation or feces.