Comically antiquated variation on '
ironic' presently used most often to emphasise the unseriousness of a
point. 'Ironical', like many nouns accepting the -ical adjectival suffix (
e.g., poetical, hermetical, etc.) fell into disuse in favour of the shorter -
ic form (e.g., poetic, hermetic, etc.) in Early Modern English. The anachronistic 'ironical' is therefore most commonly used in current speech to suggest the absurdity of an expression.