Answer:

calmest

Answer	Crossword Clue
CALMEST	Least ruffled
CALMEST	Serene to the max
CALMEST	Most serene

CALMEST	Least rattled
CALMEST	Least disturbed.
CALMEST	Most undisturbed.
CALMEST	Most composed.
CALMEST	Most placid.
CALMEST	Most self-possessed.
CALMEST	Most relaxed
CALMEST	Most cool

CALMEST	Still the most
CALMEST	Least rocky
CALMEST	Least wavy
CALMEST	Least perturbed
CALMEST	Poised to the max

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.