Relating to or characteristic of antioptimism; expressing opposition to optimistic views; pessimistic or skeptical of favorable outcomes.
From antioptimistic + -al (adjective suffix intensifier). An older or more formal version of 'antioptimistic,' using the -al suffix common in earlier English.
The -al ending (like in 'historical' or 'magical') was especially popular in older formal writing—so 'antioptimistical' sounds like something a 19th-century philosopher would have written!
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