What is a Shifting 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.}

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

You can use the examples below to find the property:

Here’s a CSV version:

ace,jack
army,navy
commute,common  
effort,stress
egg,apple
grumpy,sad
influx,income  
Knox,fort
moth,bug
obey,allow
solo,alone
wonky,wobbly
wrens,crows
yolk,white

Can you tell me the rule?

Hint 1: