The most common and most likely answer to this crossword clue is the 9 letter word STINGIEST
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The straight part
We know that "Least hospitable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case least hospitable = stingiest.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 STINGIEST mean?
STINGIEST adjective- Unwilling to spend, give, or share; ungenerous; mean
- Small, scant, meager, insufficient
- Stinging; able to sting.