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 Tower Word™.
Use the following examples below to find the rule.
And, if you want to analyze, here is a CSV version:
Tower Words™,Not Tower Words™ ANVIL,HAMMER AX,SWORD COOCOO,RAVEN DRUG,COCAINE FILET,BEEF HUG,KISS KUSSOS,WHAT LEZ,PLEASE PI,MATH TILT,SLANT US,ME VILE,GOOD WHY,NOT XU,CHINA ZEE,EASY