The most common and most likely answer to this crossword clue is the 6 letter word SCURVY
S
C
U
R
V
Y
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The straight part
We know that "Low-down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case low-down = scurvy.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 SCURVY mean?
SCURVY noun- A disease caused by insufficient intake of vitamin C leading to the formation of livid spots on the skin, spongy gums, loosening of the teeth and bleeding into the skin and from almost all mucous membranes.
- Covered or affected with scurf or scabs; scabby; scurfy; specifically, diseased with the scurvy.
- Contemptible, despicable, low, disgustingly mean.