Question

What is the significance of repetition of the word absurd in the importance of being earnest?

Answer 1

In "The Importance of Being Earnest" Oscar Wild uses irony to transmit a meaning that is opposite of its real meaning, specially situational and dramatic irony.

The play is a "satire", a genre intended to ridicule for the purpose of entertainment and very often to expose flaws in society.

So the use of meaningless dialogues is a common practice in the genre, and the repetition of the word absurd is an example of it, provoking an incoherent situation, to criticize the Victorian society of that time by ridiculing it.

Answer 2

The significance of the repetition of the word absurd in "The Importance of Being Earnest" is that Jack uses the word a lot to describe the behaviors that seem  strange  to him.