Without chance or fortune; certain or inevitable; or alternatively, lacking opportunity or possibility.
From chance + -less (Old English suffix -leas meaning without or deprived of). This represents the opposite formation to 'chanceful' using the antonym suffix.
The pair 'chanceless/chanceful' shows how English creates opposites through competing suffixes: -ful means 'full of' while -less means 'without,' so the same root word can spawn antonyms in different directions.
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