This is the 1221st most frequent Russian word.
личных
The Russian word "личных" means "personal" (genitive or plural form).
In this sentence, 'личных' is used as an adjective meaning 'personal', describing the possessions as being of a private and personal nature.
У меня есть несколько личных вещей, которые я ценю больше всего.
I have several personal possessions that I value the most.
Here, 'личных' modifies 'данным', emphasizing the private and sensitive nature of the data.
Доступ к личным данным строго ограничен.
Access to personal data is strictly limited.
In this case, 'личных' pertains to 'врагов', indicating enemies on a personal level or directly related to the individual.