chasmatical
Chasmal (of or like a chasm).
rare
Pray, Madam! let me have none of your chasmatical impertinence.
Where it comes from
From Ancient Greek χασματικός (khasmatikós) + -al. By surface analysis, chasm + -atic + -al.
Adapted from the Wiktionary entry chasmatical (CC BY-SA 4.0).