Learn Polish: Ten wścibski mężczyzna podgląda nas przez okno. - This nosy man is spying on us through the window.

In this lesson, pod- adds a sense of doing something secretly or stealthily. The root is related to looking (as in oglądać, to watch). By adding pod-, the neutral act of watching becomes podglądać: to peep, to spy on, or to watch secretly.

What is the origin of the adjective wścibski (nosy)?

It comes from the verb wścibiać (to stick or poke into). You will often hear it in the popular idiom wścibiać nos w nie swoje sprawy (to stick one's nose into someone else's business). A wścibski mężczyzna is essentially a man who pokes his nose where it does not belong!

Why is the imperfective form podgląda used here instead of a perfective equivalent?

The sentence describes an ongoing, continuous action happening right now (is spying), so we need the imperfective verb podglądać. If he had successfully sneaked a quick peek as a one-time completed action, you would use a perfective form like podglądnąć or podpatrzeć.

Why does the sentence use przez okno and not a locative form like w oknie?

The preposition przez (meaning through or across) focuses on the trajectory of the gaze passing from the outside to the inside, which requires the accusative case. Because okno (window) is a neuter noun, its accusative form looks exactly identical to its nominative dictionary form.