What is a Personal 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 conforms to a special rule, I call it a Personal Word™.

Use the examples below to find the rule.

CSV version:

Personal Words™,Not Personal Words™
PUBLIC,PERSONAL
GOVERNMENT,BUREAUCRACY
LAYOUT,CHART
SHEPHERD,MARSHALL
ANSWER,FEEDBACK
MOUSETRAP,UNDERNEATH
CRIBBAGE,BLACKJACK
FUNDAMENTAL,NUCLEAR
THEREFORE,ERGO
SHELL,COVER
MUST,SHOULD
AWESOME,WONDERFUL
STILL,ANYMORE

The puzzle relies on the series’ inbuilt assumption, that each word can be tested for whether it is a Personal Word™ without relying on the other words.

These are not the only examples of Personal Words™, many more exist.