This is the 22nd most frequent Serbian word.
јер
The Serbian word "јер" means "because" in English.
In this sentence, 'јер' introduces a causal relationship; it means 'because' and explains the reason for going home earlier.
Идем раније кући јер морам да спремим вечеру.
I am going home earlier because I need to prepare dinner.
In this example, 'јер' provides the reason for not coming, connecting the action of not coming with the explanation.
Он није дошао, јер је био болестан.
He did not come because he was sick.
Here, 'јер' connects two clauses and explains why the person shouldn't worry; it indicates the reason.