irreducibly

Etymology tree
Proto-Indo-European *né
Proto-Indo-European *n̥-
Proto-Italic *n̥-
Latin in-bor.
Middle English in-
English ir-
English reduce
Proto-Indo-European *-tḗr
Proto-Indo-European *-dʰlom
Proto-Indo-European *-dʰlis
Proto-Italic *-ðlis
Latin -bilis
Latin -ibilis
Old French -ibleder.
Middle English -ible
English -ible
English reducible
English irreducible
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 irreducibly
From irreducible + -ly.