stay stock still

stay stock still

To not move at all. You kids need to stay stock still out here until the firemen are done investigating the building, OK? I didn't want my grandmother to catch me rooting through her jewelry box, so when I heard her in the hallway, I got in the closet and stayed stock still until she left.
See also: stay, still, stock
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

be, stay, stand, etc. ˌstock-ˈstill

be, stay, etc. still, without moving at all: When I heard footsteps on the stairs, I stood stock-still and held my breath.
Stock-still means as still as a stock (= an old word for a piece of wood).
Farlex Partner Idioms Dictionary © Farlex 2017
See also: