Nannan

Figure of speech. While exchanging words with Joseph Patrick Nannetti over the unholy racket of the printing press, Bloom thinks, "He doesn't hear it. Nannan. Iron nerves." Nannan may be a nickname familiar to Dubliners, but in a chapter filled to bursting with rhetorical figures it also registers as a conscious manipulation of language. One possible label for it is antisthecon, the substitution of one letter, sound, or syllable for another within a word. Or a different kind of metaplasm, apocope, might apply.

John Hunt 2023

Two species of clown fish. Source: www.researchgate.net.