This is the 17568th most frequent Polish word.
zdały
"Zdały" means "passed" (referring to females or plural subjects) in English.
Here, "zdały się" is part of a fixed expression meaning "proved to be," showing an outcome.
Starania zespołu zdały się na nic.
The team's efforts came to nothing.
In this sentence, "zdały" is the third-person plural feminine past tense of "zdać," meaning "passed" or "succeeded in."
Studentki zdały egzamin z matematyki.
The female students passed the mathematics exam.
The word "zdały" here functions as part of the phrase "zdały egzamin," figuratively indicating practical applicability.