Bloody, bloodstained, or characterized by gore; an extremely rare variant of 'cruent'.
From Latin 'cruentus' with the English adjectival suffix '-ous', creating a doubly-marked adjective that combines Latin and English morphology in an archaic fashion.
The '-ous' ending usually comes with Latinate words, but 'cruentous' seems redundant since 'cruent' already ends in a way that sounds adjectival—it's the kind of over-marking that archaic English sometimes produced.
Complete word intelligence in one call. Free tier — 50 lookups/day.