This is the 1910th most frequent Polish word.
solidarność
"Solidarność" means "solidarity" – unity and mutual support within a group.
Here, 'solidarność' is used as a noun to describe a general human quality of mutual support.
Solidarność to cecha, która pozwala ludziom współdziałać w trudnych sytuacjach.
Solidarity is a trait that enables people to cooperate in difficult situations.
In this sentence, 'solidarnością' is in an instrumental case, showing active mutual assistance among individuals.
W czasie kryzysu wszyscy wykazali się solidarnością, pomagając sobie nawzajem.
During the crisis, everyone demonstrated solidarity by helping each other.
'Solidarność' here is a proper noun referring to the historical Polish movement.