This is the 148th most frequent Lithuanian word.
greitai
Quickly.
In this sentence, "greitai" is used as an adverb describing the speed or promptness of the action of returning home.
Mes greitai grįšime namo.
We will return home quickly.
Here "greitai" again functions as an adverb, referring to the speed of events occurring.
Pastaruoju metu viskas vyksta labai greitai.
Recently, everything happens very quickly.
In this example, "greitai" is used to denote the speed at which the subject learns.