This is the 13733rd most frequent Spanish word.
rápidas
"Rápidas" means "fast" or "rapid" (feminine plural form).
In this sentence, 'rápidas' is used as an adjective modifying 'corrientes', which means 'currents', describing the speed or nature of the river's flow.
Las rápidas corrientes del río hacen que sea peligroso nadar.
The swift currents of the river make it dangerous to swim.
Here, 'rápidas' is an adjective modifying 'decisiones', referring to the hurried manner in which decisions were made without careful deliberation.
El equipo casi pierde el juego por sus rápidas decisiones.
The team almost lost the game due to their hasty decisions.
In this case, 'rápidas' describes 'patas', which means 'legs', emphasizing their ability to move quickly and aiding in escape.