exceptionably

Etymology tree
Proto-Indo-European *h₁éǵʰ
Proto-Indo-European *-s
Proto-Indo-European *h₁éǵʰs
Proto-Italic *eks
Latin ex
Latin ex-
Proto-Indo-European *kap-
Proto-Indo-European *-yéti
Proto-Indo-European *kapyéti
Proto-Italic *kapjō
Old Latin kapiō
Latin capiō
Latin excipiō
Proto-Indo-European *-tis
Proto-Indo-European *-Hō
Proto-Indo-European *-tiHō
Proto-Italic *-tiō
Latin -tiō
Latin exceptiōder.
Old French excepcion
Anglo-Norman excepciounbor.
Middle English exception
English exception
Proto-Indo-European *-tḗr
Proto-Indo-European *-dʰlom
Proto-Indo-European *-dʰlis
Proto-Italic *-ðlis
Latin -bilis
Latin -ābilis
Old French -ablebor.
Middle English -able
English -able
English exceptionable
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 exceptionably
From exceptionable + -ly.