Answer:

coolest

Answer	Crossword Clue
COOLEST	Least worried
COOLEST	Most unflappable
COOLEST	Calmest.

COOLEST	Least torrid.
COOLEST	Least ardent.
COOLEST	Most collected
COOLEST	Most composed
COOLEST	Most unruffled
COOLEST	Most imperturbable
COOLEST	Least perturbable
COOLEST	Least ruffled

COOLEST	Maximally hip
COOLEST	Most hip
COOLEST	The Fonz, compared to the rest
COOLEST	Least nerdy

Crossword

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