Synonyms of eerily

2 Syllables
weirdly, grimly
3 Syllables
fearfully, spectrally, creepily, spookily, chillingly, hauntingly, monstrously
4 Syllables
sinisterly, otherworldly, ominously, unusually, bizarrely, mysteriously, uncannily, bloodcurdlingly, formidably, unnervingly
5 Syllables
fantastically, forebodingly
6 Syllables
phantasmatically, preternaturally, supernaturally