In Waiting for Godot, Lucky the slave is forced to give a speech after his feeble dancing fails to impress Estragon and Vladimir. As he begins his speech, he starts talking
of a personal God quaquaquaqua with white beard quaquaquaqua outside ...
The "quaquaquaqua" here is the same as saying "blah, blah, blah" or "et cetera, et cetera, et cetera." In other words, Lucky is implying that he doesn't have to continue to describe the nature and the appearance of the Christian God because his audience already knows all this, so he can move on with what he has to say.
However, qua is also a Latin word that means "whereby," a term which was often used by scholars in the earlier part of the twentieth century. Therefore, the word becomes part of the overall parody of pretentious academic language that Lucky's speech is. Quaquaqua is a non-word, like the word anthropopopometry that Lucky uses. These terms seem academic while having no real meaning. Like the word quaquaqua, Lucky's speech sounds like a duck quacking, saying a lot of nothing with gusto and energy.
Lucky's speech reveals that academic or scholarly explanations for the meaning of life basically offer little more explanation than that God and meaning are unknowable. He exhausts himself alluding to false scholars, such as Fartov (whose name sounds like "fart off"), whose words are nonsense.