This is the 286th most frequent Hebrew word.
שכבר
"That already."
In this sentence, "שכבר" provides information about a prior action (meeting with the person) related to the noun (the person).
האדם שכבר נפגשנו איתו התקשר שוב.
The person whom we already met with called again.
Here, "שכבר" specifies a state (being closed) that had occurred before the main action (going to the store).
הלכתי לחנות שכבר הייתה סגורה.
I went to the store which was already closed.
In this sentence, "שכבר" introduces a relative clause and emphasizes that the action (answer being given) occurred previously.