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 conforms to a special rule, I call it a Waterfall Word™.
Use the following examples below to find the rule.
And, if you want to analyze, here is a CSV version:
Waterfall Words™,Not Waterfall Words™ ANTACID,MEDICINE BEAMED,SMILED COSMOS,UNIVERSE CRAMPS,PAIN MEANT,IMPLIED MEANY,BULLY PANEL,FRAME RABID,SICK RAMPANT,WILD SCRAM,GET TACOS,CHIPS TAXES,FINES VISCUS,VISCERA WAVY,BUMPY