shadow

US /ˈʃæd.oʊ/
UK /ˈʃæd.oʊ/
"shadow" picture
1.

a dark area or shape produced by a body coming between rays of light and a surface.

:
The tree cast a long shadow on the grass.
He saw his own shadow in the dim light.
2.

a person or thing that is a weak or inferior version of something else.

:
The new movie is just a shadow of the original.
He was a mere shadow of his former self after the illness.
1.

follow and observe (someone) closely and secretly.

:
The detective decided to shadow the suspect.
She felt like someone was shadowing her every move.