This is the 126th most frequent Slovak word.
lebo
"Because" or "for (as a reason)."
In this usage, 'lebo' introduces the cause or justification for needing to be quick.
Musíme byť rýchli, lebo čoskoro začne pršať.
We have to be quick because it will soon start to rain.
Here, 'lebo' is used to explain why the situation is considered strange, providing the rationale.
Je to zvláštne, lebo na stole boli dve misky, ale len jedna bola špinavá.
It's strange because there were two bowls on the table, but only one was dirty.
Here, 'lebo' is used as a conjunction meaning 'because', explaining the reason for not going to dinner.