placid

Adjective
  1. (of a body of water) free from disturbance by heavy waves (synset 300303750)
    "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"; "unruffled water"
  2. Not easily irritated (synset 301137986)
    "an equable temper"; "not everyone shared his placid temperament"; "remained placid despite the repeated delays"

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