Webster's Revised Unabridged Dictionary · 1913

Bopeep

Bopeep ({not transcribed}) , noun

[Bo + peep.]

The act of looking out suddenly, as from behind a screen, so as to startle some one (as by children in play), or of looking out and drawing suddenly back, as if frightened.
I for sorrow sung, That such a king should play bopeep, And go the fools among. — Shakespeare