Learn English – Difference between “shake”, “tremor”, “shiver”, “tremble”

This piece from the grammarist discusses about the usage of "concerning" and its possible overtones as "a cause of concern", but apart from that I think that it is interchangeable with "regarding":

• One complaint against concerning does stand up: The word is also a preposition meaning in reference to or regarding, and the adjectival concerning can cause confusion when readers or listeners initially interpret it as the preposition.

• For instance, if you hear someone say, “His email was concerning,” you might at first expect something to come after concerning. This complaint isn’t a rock-solid case, though, as many words in English have multiple functions, but it’s a good reason for those inclined against the word to continue avoiding it.

Actually checking with Ngram, (a question concerning vs a question regarding) it appears that "concerning" used as a preposition meaning "regarding" is quite common.

Ultimately, what makes a clearer distinction between the words "public figure" and "celebrity" or "famous?" Many people use them all synonymously, but the reality is that they aren't all equal.

People do not use these synonymously.

No one says 'public figure' at all except as a legal term, especially for those extended fewer privacy protections. It essentially means 'someone who has put themselves out there' and is thus fair game for public attacks. The precise definition varies by jurisdiction, though.

Celebrity is now the agent noun of famous, much moreso than its original sense of someone who is celebrated. Its synonym, though, is the noun phrase famous person, not the adjective famous.