This is the 8115th most frequent Polish word.
online
The Polish word "online" means "connected to or available through the internet."
Here, 'online' is used as an adverb to indicate the mode by which the action (watching movies) is performed - through the internet.
Czy oglądasz filmy online?
Do you watch movies online?
Here, 'online' functions as an adjective describing the noun 'shopping', indicating that the shopping is done on the internet.
Online zakupy stają się coraz bardziej popularne.
Online shopping is becoming more and more popular.
In this sentence, 'online' is also used as an adverb to specify the work's mode of execution, indicating it is carried out using internet connectivity.