# What is a Bumpy Word™?

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.

If a word has a certain property, I call it a Bumpy Word™.

You can use the examples below to find the property:

Bumpy™ Not Bumpy™
ARMY NAVY
BUMPING JERKING
CABAL CONSPIRACY
CHASER PURSUER
COALESCE SOLIDIFY
COMPOSITE DIVERSE
CRANK TURN
CRAZY INSANE
EXAMINATION TEST
FERAL UNCIVILIZED
HIGHER GREATER
JUMPING LEAPING
ORATOR SPEAKER
QUALITATIVE SUBJECTIVE
SQUASH CRUSH
THRASH SPASM
TRUSTING BELIEVING
UPWARD SKYBOUND
VAULTING CAVERNOUS
WELDED FUSED

Here is a CSV version:

Bumpy™,Not Bumpy™
ARMY,NAVY
BUMPING,JERKING
CABAL,CONSPIRACY
CHASER,PURSUER
COALESCE,SOLIDIFY
COMPOSITE,DIVERSE
CRANK,TURN
CRAZY,INSANE
EXAMINATION,TEST
FERAL,UNCIVILIZED
HIGHER,GREATER
JUMPING,LEAPING
ORATOR,SPEAKER
QUALITATIVE,SUBJECTIVE
SQUASH,CRUSH
THRASH,SPASM
TRUSTING,BELIEVING
UPWARD,SKYBOUND
VAULTING,CAVERNOUS
WELDED,FUSED


In a word,

If a letter occurs (in the alphabet) later than the previous letter in the word, let us call it a "rise", otherwise, it's called a "fall". Note that the first letter of a word is neither of these.

Then a Bumpy word is

A word in which "rise"s and "fall"s occur alternately.

Example:

A,R(rise),M(fall),Y(rise) | N,A(fall),V(rise),Y(rise).

Why "Bumpy"?

For a Bumpy word, imagine plotting the letter-indexes in the order they occur in the word. For example, "BUMPING" would be plotted as follows:

Alternation between "rise" and "fall" obviously means that the graph is more "uneven" or "bumpy".

• Should Ankoganit add that alternating "rise" and "fall" is what makes it called bumpy...? The answer looks pretty clear to me. – user29705 Sep 9 '16 at 12:32
• This is clearly missing the phrase "simply take the derivative of distance through the alphabet with respect to distance through the word". – Jonathan Allan Sep 9 '16 at 14:57