IPA: //ˈræpɪdər//
KK: /ˈræpɪdər/
Faster than something else; having a higher speed.
The cheetah is rapider than the lion when it comes to sprinting.
Rapider → It is formed from "rapid" (from Latin "rapidus", meaning swift or quick) and "-er" (meaning one who or that which). The word "rapider" means one that is more swift or quick than another.
Think of 'rapid' meaning swift, and remember that 'rapider' refers to something that is more swift.