5 words for EIOSST 1-letter words

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1 letter (5)

e i o s t
Boast – black bird
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C
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Hint 1 meaning
A bird, usually black, of the genus Corvus, having a strong conical beak, with projecting bristles. It has a harsh, croaking note. See Caw.
Hint 2 anagram
OWCR
Hint 3 another clue
Ridicule
10 +1