This is the 15840th most frequent Polish word.
tajemnicami
"Secrets" (instrumental plural form).
The word 'tajemnicami' is used in its instrumental plural form, referring to secrets that the subject possesses and shares.
Ona często dzieli się swoimi tajemnicami z bliskimi przyjaciółmi.
She often shares her secrets with close friends.
The word 'tajemnicami' is used to denote that secrets are the contents or metaphorical characteristic of the chest, again in the instrumental case plural form.
Tajemnicami pełna jest ta stara skrzynia na strychu.
The old chest in the attic is full of secrets.
Here, 'tajemnicami' serves to express the objects of the analysis or activity being carried out by the subject, maintaining the instrumental plural usage.