This is the 15197th most frequent Polish word.
sekretów
"Secrets" (genitive plural form of "sekret").
The word 'sekretów' is the plural genitive form of 'sekret', indicating possession or association with 'of secrets'.
Odkryłem wiele ukrytych sekretów w starych książkach.
I discovered many hidden secrets in old books.
Here, 'sekretów' again serves as the plural genitive form, used within a negated sentence to express absence.
Nasza przyjaźń nie potrzebuje tajemnic ani sekretów.
Our friendship needs neither mysteries nor secrets.
In this usage, 'sekretów' connects the adjective 'zagubionych' to the noun 'secrets', indicating it refers to these specific kinds of secrets in the plural genitive form.