mysticly

Etymology tree
Ancient Greek μῡ́ω (mū́ō)
Proto-Indo-European *-eti
Proto-Indo-European *-eyéti
Proto-Indo-European *-esyéti
Proto-Indo-European *-éh₁ti
Proto-Indo-European *-yeti
Proto-Indo-European *-éh₁yeti
Proto-Indo-European *-yeti
Proto-Indo-European *-éyeti
Ancient Greek -έω (-éō)
Ancient Greek μῠέω (mŭéō)
Proto-Indo-European *-tósder.
Ancient Greek -της (-tēs)
Ancient Greek μῠ́στης (mŭ́stēs)
Proto-Indo-European *-kos
Ancient Greek -κός (-kós)
Ancient Greek -ῐκός (-ĭkós)
Ancient Greek μῠστῐκός (mŭstĭkós)der.
Latin mysticus
Old French mistiqueder.
English mystic
Proto-Indo-European *leyg-der.
Proto-Germanic *līkąder.
Proto-Germanic *-līkaz
Proto-Germanic *-ê
Proto-Germanic *-līkê
Proto-West Germanic *-līkē
Old English -līċe
Middle English -ly
English -ly
English mysticly
From mystic + -ly.