Inaudible
(adj) too quiet to be heard
Syn: silent, imperceptible
Ant: audible, loud
Implausible
(adj) not believable, highly unlikely
Syn: unbelievable, dubious
Ant: plausible, believable
Subdued
(adj or verb) quiet, calm
Syn: tranquil, restrained
Ant: agitated, energetic
Audacity
(noun) boldness, often in the face of authority
Syn: brazenness, impudence
Ant: timidity, shyness
Proliferate
(verb) to grow in number
Syn: reproduce, multiply
Ant: die off, decline
Satiate
(verb) to satisfy a desire, often for nourishment
Syn: fill, satisfy
Ant: starve, do without
Placate
(verb) to soothe or settle
Syn: appease, mollify
Ant: anger, antagonize
Steadfast
(adj) not subject to change
Syn: strong, resolute
Ant: weak, wavering
Inconspicuous
(adj) hard to see, not noticeable
Syn: hidden, concealed
Ant: conspicuous, obvious
Eschew
(verb) to avoid habitually
Syn: shun, abstain from
Ant: seek out, pursue
Innocuous
(adj) harmless
Syn: benign, inoffensive
Ant: harmful, dangerous
Bellicose
(adj) warlike, aggressively violent
Syn: hostile, belligerent
Ant: peaceful, pacifist
Unanimity
(noun) agreement from all, complete unity
Syn: accord, unison
Ant: discord, disagreement
Fallacy
(noun) a false idea or argument, a lie OR a deceptive appearance
Syn: mistake, error OR disguise, deceit
Ant: truth, fact
Brevity
(noun) briefness
Syn: terseness, compactness
Ant: long-windedness, verbosity
Immutable
(adj) unchanging, stable
Syn: permanent, absolute
Ant: changing, mutable
Nugatory
(adj) of no importance
Syn: trivial, inconsequential
Ant: important, significant
Frivolous
(adj) unimportant or lacking seriousness
Syn: trivial, silly
Ant: serious, important
Superfluous
(adj) unnecessary or extravagant
Syn: extraneous, needless
Ant: necessary, integral
Extraneous
(adj) not belonging OR not an important part, not essential
Syn: alien, external OR superfluous, irrelevant
Ant: belonging to, fitting in OR vital, essential