While I was reading a book, the following sentence caught my eye.

Sincerity and courtesy are of desirable character traits.

I saw this kind of sentence before, but never fully understood why the preposition 'of' is used. If I remove the preposition 'of', the sentence become..

Sincerity and courtesy are desirable character traits.

To me, both sentences convey the same meaning. I have also seen sentences like..

The man is of great importance.

So do we really need a preposition in these scenarios? If yes, then why and how to use the preposition 'of' properly with 'is/are'?

  • 2
    nounA is of noun B, means nounA has nounB, but it doesn't mean nounA is nounB.
    – Elizabeth
    Mar 19, 2020 at 13:47
  • What book? Where? Mar 19, 2020 at 18:01
  • Would you please approve an answer if which does help you? If none answers your question, would you please leave some comments to ask for more explanation about some aspect.
    – WXJ96163
    Mar 20, 2020 at 7:34
  • @WXJ96163 Sorry for this delayed response. Mar 23, 2020 at 9:12
  • @MichaelHarvey It was a collection of short stories. I read it while I was waiting in a hotel lobby. Can't remember the writer’s name at the moment. Mar 23, 2020 at 9:17

2 Answers 2


The first example is ungrammatical. The second example is correct.
The third example is grammatical, but it is not comparable to the second.

The second example "sincerity and courtesy are ... traits", equates the predicate to the subject.

The third example doesn't equate the predicate to the subject, but says that the subject has a particular property.
This corresponds to a particular meaning of "of":
M-W "of" 10
"—used as a function word to indicate a characteristic or distinctive quality or possession, for example, a woman of courage."


Be of noun/noun phrase is a commonly used expression to emphasize the characteristic described by "noun/noun phrase".

Your example

The man is of great importance.


The man is very great important.

in the meanwhile, emphasizes the importance of that man.

  • "The man is very great important" is not grammatical.
    – Billy Kerr
    Oct 15, 2023 at 9:37

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