Answer:

stiffen

Answer	Crossword Clue
STIFFEN	Become rigid
STIFFEN	Tighten up
STIFFEN	Brace oneself

STIFFEN	Use starch
STIFFEN	Add starch to
STIFFEN	Jell.
STIFFEN	Tense.
STIFFEN	Add starch
STIFFEN	Become less flexible
STIFFEN	Necks might do it
STIFFEN	Exhibit stage fright

STIFFEN	Get starched?
STIFFEN	Brace for a shock
STIFFEN	Exhibit fright, in a way

Crossword

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