_{In the spirit of the What is a Word™/Phrase™ series started by JLee, a special brand of Phrase™ and Word™ puzzles.}

If a word conforms to a special rule, I call it a Fortunate Word™.
Use the following examples below to find the rule.

                                        * These are Very Fortunate Words™

And, if you want to analyze, here is a CSV version:

Fortunate Words™,Not Fortunate Words™
MY,OUR
NOW,AGO
CAR,OIL
SINK,SAIL
REAL,HOAX
NUTTY,CHEWY
SHEEP,GOATS
BLAME,ACCUSE
EIGHTH,FOURTH
GLANCE,VISION
YELLOW,ORANGE
PARCEL,PACKAGE
PROTECT,ASSAULT
CLUSTER,COMPLEX
DECREASE,INCREASE
EXERCISE,FEEDBACK
TREATMENT,OPERATION
PRINCIPLE,PRINCIPAL
REPEATEDLY,CONTINUOUS
CENTERFOLDS*,SUPERMODELS
ENTREPRENEUR,PROFESSIONAL
DISTRESSINGLY*,UNFORTUNATELY

The puzzle satisfies the series’ inbuilt assumption, that each word can be tested for whether it is a Fortunate Word™ without relying on the other words.
These are not the only examples of Fortunate Words™; many more exist.

What is the special rule these words conform to?

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Hints

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