noun / verb
peek
PEEK/pˈik/
A brief look, often taken secretly.
She peeks around the partly open door.

Etymology
Middle English piken already described a quick, sly look, so the modern sense preserves the same idea of brief or secret looking. Its deeper origin is unknown.
In context
… I just had to creep over to the edge to peek my head over to appraise how high up I am before that first landing …