filamentously

Etymology tree
Proto-Indo-European *gʷʰiH-(s-)lo-der.
Proto-Italic *fī(s)lom
Latin fīlum
Proto-Indo-European *-h₂
Proto-Indo-European *-éh₂
Proto-Indo-European *-yéti
Proto-Indo-European *-eh₂yéti
Proto-Italic *-āō
Latin -ō
Late Latin fīlō
Proto-Indo-European *-mn̥
Proto-Indo-European *-mn̥tom
Proto-Italic *-mentom
Latin -mentum
Medieval Latin fīlāmentumbor.
English filament
Proto-Indo-European *h₃ed-
Proto-Indo-European *-os
Proto-Indo-European *h₃édosder.?
Proto-Italic *-ōtsos or *-otsos
Latin -ōsus
Old French -usbor.
Middle English -ous
English -ous
English filamentous
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 filamentously
From filamentous + -ly.