This is the 14106th most frequent Polish word.
pozostaliby
"Pozostaliby" means "they would remain" in English.
In this sentence, 'pozostaliby' is used as a hypothetical form of 'pozostawać,' indicating an imagined scenario where someone would remain in a certain state, condition, or situation.
Gdyby nie pomoc, pozostaliby bez schronienia.
If it weren't for the assistance, they would have remained without shelter.
Here, 'pozostaliby' again expresses a conditional past-tense hypothetical situation about staying in a location depending on external conditions.
Pozostaliby na plaży do zachodu słońca, gdyby pogoda pozwoliła.
They would have stayed on the beach until sunset, if the weather had allowed.
In this instance, 'pozostaliby' denotes a hypothetical persistence or adherence to one's own stance in a contrary situation.