- a lake of tranquil blue water reflecting a tranquil blue sky.
- a ribbon of sand between the angry sea and the placid bay.
- a smooth channel crossing.
- an equable temper.
- not everyone shared his placid temperament.
- remained placid despite the repeated delays.
- scarcely a ripple on the still water.
- the quiet waters of a lagoon.
- unruffled water.