This is the 17362nd most frequent Polish word.
zapiętych
"Zapiętych" means "fastened" or "buttoned up" in English.
Here, 'zapiętych' refers to individuals 'persons' and metaphorically suggests they were equipped or secured with something specific (like tight clothing).
Ubrania osób zapiętych szybko przyciągały wzrok.
The clothes of the fastened persons quickly caught attention.
Here, 'zapiętych' (fastened) is used as a masculine adjective agreeing with 'pasy' (belts), showing an action completed and emphasizing the state of being fastened.
Siedząc w samochodzie, miałem wszystkie pasy zapiętych.
Sitting in the car, I had all the seat belts fastened.
In this context, 'zapiętych' describes the buttons ('guzików') and indicates that they were supposed to be fastened but are missing.