Precipitate.
another way of saying rapind increase is 'the population increased rapidly'.
quickly or rapidly.
Quickly, fast.
Running at the mouth
The word 'rapidly' is an adverb, a word that modifies a verb, an adjective, or another adverb. Example:The boy rapidly ran to catch the ball before it could hit the ground.
rapidly, speedily
Addition.
Rapid is another word for quick or fast. Rapidly is an adverb, and as such is used to describe an action.The rabbit ran rapidly through the forest.Lets get this done rapidly, we're not getting paid overtime here.The lady spoke in French so rapidly, I had a lot of trouble understanding what she was saying.
Frantically. or maybe furiously? also frenetically.
No - the word "rapidly" is an adverb.
Enlarge or augment
increase your pace