This is the 753rd most frequent Czech word.
nebyly
"Were not"
The word 'nebyly' describes the negation of satisfaction in the past, concerning a group.
Nebyly spokojeni s výsledkem své práce.
They were not satisfied with the result of their work.
Here, 'nebyly' is used as the past-tense plural form of 'to be' (negated form). It references the conditions which is contextually plural.
Byli jsme na výletě, ale podmínky nebyly ideální.
We went on a trip, but the conditions were not ideal.
'Nebyly' conveys the negated past tense indicatory that the objects 'detaily' (details) were not displayed.