This is the 12386th most frequent Polish word.
musiałaby
"Musiałaby" means "she would have to" or "she would need to" in English.
The word 'musiałaby' is a conditional form of 'musieć,' implying a necessity contingent upon certain conditions.
Ona musiałaby iść do sklepu, gdyby miała czas.
She would have to go to the store if she had time.
The use of 'musiałabyś' shows necessity as applying hypothetically to the listener; the action is conditional.
Musiałabyś zrozumieć zasady gry, zanim zaczniesz grać.
You would need to understand the rules of the game before you start playing.
In this case, 'musielibyśmy' highlights the hypothetical requirement for a group to act to meet a condition.