eldritch

adjective

Comparative: eldritcher, more eldritch
Superlative: eldritchest, most eldritch
Approximative: eldritchish

Strange; fearful; weird; eerie.

Examples:

Bruno prehardened his mind not to be frightened like some kind of cowardly milksop. After all, he had endured an encounter with a luminous phantom in an eldritch old cellar last month. And he also heroically overcame his own kidnapping! (Source: J∙ Okram - The Mystery of the Rammed Key.)