1) Least agitated 2) Least perturbed 3) Least rocky 4) Least stormy 5) Least wavy 6) Most cool 7) Most placid 8) Most self-possessed 9) Most serene 10) Most tranquil 11) Most under control 12) Serene to the max 13) Still the most Found on https://www.crosswordclues.com/clue/calmest
1) Least agitated 2) Least perturbed 3) Least rocky 4) Least stormy 5) Least wavy 6) Most cool 7) Most placid 8) Most self-possessed 9) Most serene 10) Most tranquil 11) Most under control 12) Serene to the max 13) Still the most