This is the 42nd most frequent Czech word.
kvůli
"Kvůli" means "because of" or "due to."
In this sentence, 'kvůli' is used to express the reason or cause for the apology, indicating that the delay is the cause.
Musím se omluvit kvůli zpoždění.
I have to apologize because of the delay.
Here, 'kvůli' demonstrates the reason for staying at home, referring to the illness as the cause.
Zůstal doma kvůli nemoci.
He stayed at home because of illness.
This example uses 'kvůli' to explain the reason for arriving late, attributing it to a traffic jam.