This is the 2692nd most frequent Spanish word.
fronteriza
Border-related.
In this sentence, 'fronteriza' describes a zone or area that is situated close to the border between two countries.
La zona fronteriza entre los dos países es cuidadosamente vigilada.
The border area between the two countries is carefully monitored.
Here, 'fronteriza' modifies 'policía' to indicate the specific police force responsible for border security.
La policía fronteriza detuvo a varios viajeros durante la inspección.
The border police detained several travelers during the inspection.
In this case, 'fronteriza' describes an organization that operates or has functions related to the border or border issues.