Which literary technique is austen using in mrs. dash wood reference to “wit” in the excerpt

The exact excerpt is:

Mr. Palmer made her no answer, and did not even raise his eyes from the newspaper.

"Mr. Palmer does not hear me," said she, laughing; "he never does sometimes. It is so ridiculous!"

This was quite a new idea to Mrs. Dashwood; she had never been used to find wit in the inattention of any one..."

This excerpt is from Jane Austen's 1811 novel Sense and Sensibility. The use of the wit shows the dramatic irony. Wit means cleverness and intelligence. In the excerpt, Mrs. Dashwood ironically mentions that how Mr. Palmer's inattentiveness contains such an intelligence. In reality, it is not an intelligence. One crucial point is that it is a dramatic irony, not a verbal irony. Indeed, the former one shows that the readers are already aware of the situation.  

the whisper is the answer, hope this : )

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