inaudible
UK[ɪnˈɔːdəbl]US[ɪnˈɔːdəbl]
adj
impossible to hear
Morpheme Breakdown
in
aud
ible
in
not
aud
hear
ible
capable of
Etymology
the word 'inaudible' is a direct borrowing from late latin 'inaudibilis', which itself was formed within latin from the native elements 'in-' (not) and 'audibilis' (able to be heard). the root 'aud-' traces back to the proto-indo-european root h₂ew- meaning 'to perceive' or 'to see', which interestingly broadened in latin to specifically denote hearing. the suffix '-ibilis' is a productive latin adjectival suffix creating passive potential meanings. thus, the literal construction 'not able to be heard' has remained perfectly transparent and unchanged in its semantic logic from its latin origin to its modern english usage, precisely describing sounds that fall below the threshold of human perception.
Analysis
Structure: in (not) + aud (hear) + ible (capable of)
in- (latin, prefix meaning 'not'); aud- (latin root 'audire', meaning 'to hear'); -ible (latin suffix '-ibilis', meaning 'capable of, able to be')
Examples
the speaker's voice was almost inaudible over the noise of the machinery.
dogs can hear frequencies that are inaudible to the human ear.
she whispered an inaudible apology before leaving the room.