neuter singular accusative (or nominative) of acchariya, an adjective or noun
Analysis. From Sanskrit āścaryam, an impersonal neuter denoting the marvellous or extraordinary—here in the neuter singular form.
Etymology. Sanskrit āścaryam, likely from ā- (toward, up) + √car/car (to move, act), hence "what stands forth in action"; cognate with English "scary" from Old Norse "skerra" (to frighten), though the Pali/Sanskrit root is distinct. The suffix -ya creates an adjective/noun meaning "of the nature of".
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
Lite mode — plain HTML for e-readers and old browsers. Full version