ieriest
ieriest is a term that appears sporadically in English-language text and has no widely recognized definition in standard dictionaries. In most usages, it is treated as a misspelling or typographical variant of the adjective eerie, particularly when forming its superlative.
The standard English form for the superlative of eerie is eeriest, derived by adding the suffix -est
Usage and examples: In formal writing, correct usage is eeriest: The ruins grew eerier and eeriest as