rápido
fast
rapid
happening in a short time or at a great rate
+
-ido
adjective suffix
Rápido means fast and can be thought of as related to the English word rapid0, with the -ido1 (adjective suffix1) ending.
adjective
- fastMoving or acting with great speedEl tren es muy rápido y llegará pronto. // The train is very fast and will arrive soon.
adverb
- quicklyWith great speed; quicklyCorre rápido si quieres alcanzar el autobús. // Run quickly if you want to catch the bus.