Comparative form of 'furious'; more furious or angry, though this construction is technically nonstandard English.
From furious + comparative suffix '-er.' While 'more furious' is standard, 'furiouser' appears in informal speech and creative writing, famously in Lewis Carroll's Alice in Wonderland.
Carroll's Dormouse says 'curiouser and curiouser,' and we all instantly accept 'furiouser' the same way—English loves adding '-er' to adjectives even when tradition says we should use 'more.' Language rebels against its own rules.
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