- free from disturbance
"a ribbon of sand between the angry sea and the placid bay"
"the quiet waters of a lagoon"
"a lake of tranquil blue water reflecting a tranquil blue sky"
"a smooth channel crossing"
"scarcely a ripple on the still water"
"unruf

- characterized by absence of emotional agitation
"calm acceptance of the inevitable"
"remained serene in the midst of turbulence"
"a serene expression on her face"
"she became more tranquil"
"tranquil life in the country"

1. 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.