"rapider" in the adjective sense
done or occurring in a brief period of time
"a rapid rise through the ranks"
2. rapid, speedy
characterized by speed moving with or capable of moving with high speed
"a rapid movement"
"a speedy car"
"a speedy errand boy"
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License