SuaviloquyToday’s word

tranquil

Tranquil, a.

Etymology: [L. tranquillus; probably fr. trans across, over + a word akin to quietus quiet: cf. F. tranquille. See Quiet.]

Quiet; calm; undisturbed; peaceful; not agitated; as, the atmosphere is tranquil; the condition of the country is tranquil. A style clear, tranquil, easy to follow. De Quincey.

Shades of meaning

Fernald has no entry of its own for tranquil; he lists it under calm.

Where he writes about it:

Tranquil refers to a present state, placid, to a prevailing tendency. — from calm
We speak of a tranquil mind, a placid disposition. — from calm

Synonyms

calmcollectedcomposedcooldispassionateimperturbablepeacefulplacidquietsedateself-possessedserenesmoothstillundisturbedunruffled

Antonyms

agitatedboisterousdisturbedexcitedfiercefranticfrenziedfuriousheatedpassionateragingrousedruffledstormyturbulentviolentwildwrathful

etymologyWebster’s online