This is the 512th most frequent Slovak word.
neboli
"Not to be" or "i.e." (depending on context).
In this sentence, "nebol" is the past tense of "byť" (to be) in the negative form for the singular masculine subject.
Jan nebol včera v škole.
Jan was not at school yesterday.
In this example, "neboli" functions similarly to the second sentence, describing a state of being for plural subjects in past tense.
Športovci neboli pripravení na zápas.
The athletes were not prepared for the match.
Here, "neboli" serves as the plural past tense of "byť" in the negative form, indicating the state of multiple subjects.