This is the 173rd most frequent Czech word.
nebyl
"Was not" or "were not."
Here, 'nebyl' negates the past indication of 'to be', meaning 'was not' in the context of a place or presence.
Ten muž tam nebyl.
The man was not there.
'Nebyl' forms part of the verbose compound verb structure for a hypothetical negative past conditional action.
Nebyl bych to udělal, kdybych měl na výběr.
I would not have done it if I had a choice.
Here, 'nebyl' is used to describe the nonexistence of a subject in the past in a context discussion.