knowing vs lettered

knowing is a noun but lettered is not a noun.

Word	Noun	Adjective	Verb	Adverb
knowing	Yes	Yes	No	No
lettered	No	Yes	No	No

As adjectives, knowing and lettered are synonyms defined as:

knowing and lettered: highly educated; having extensive information or understanding

Other synonyms of knowing include knowledgeable, learned, well-educated, well-read.

knowing (noun)	lettered (noun)
a clear and certain mental apprehension

knowing (adjective)	lettered (adjective)
highly educated; having extensive information or understanding	highly educated; having extensive information or understanding
evidencing the possession of inside information
characterized by conscious design or purpose
alert and fully informed