acousticky

Etymology tree
Proto-Indo-European *h₂eḱ-
Proto-Indo-European *h₂ew-
Proto-Indo-European *-s
Proto-Indo-European *h₂ṓws
Proto-Indo-European *-yéti
Proto-Indo-European *h₂ḱh₂owsyéti
Proto-Hellenic *akóuhō
Ancient Greek ἀκούω (akoúō)
Proto-Indo-European *-kos
Ancient Greek -κός (-kós)
Ancient Greek -ῐκός (-ĭkós)
Ancient Greek ᾰ̓κουστῐκός (ăkoustĭkós)bor.
Medieval Latin acousticusbor.
English acoustic
Proto-Indo-European *-kos
Proto-Germanic *-gaz
Proto-West Germanic *-g
Old English -iġ
Middle English -y
English -y
English acousticky
From acoustic + -y.