(adj): vs. noisy) -- (free of noise or uproar; or making little if any sound
(adj): failing to speak or communicate etc when expected to
(adj): vs. communicative), incommunicative -- (not inclined to talk or give information or express opinions
(adj): implied by or inferred from actions or statements
(adj): vs. explicit), inexplicit -- (implied though not directly expressed; inherent in the nature of something
(adj): not made to sound
(adj): vs. audible), unhearable -- (impossible to hear; imperceptible by the ear
(adj): having a frequency below or above the range of human audibility
(adj): vs. audible), unhearable -- (impossible to hear; imperceptible by the ear
(adj): unable to speak because of hereditary deafness
(adj): vs. articulate), unarticulate -- (without or deprived of the use of speech or words