The other dimension is that the second character 嚏 in particular is obscure: it's virtually never used in any other word than 喷嚏. In Japanese, it's a hyogai kan

The other dimension is that the second character 嚏 in particular is obscure: it's virtually never used in any other word than 喷嚏. In Japanese, it's a hyogai kanji not taught in school, meaning most people would spell it phonetically. Alas, this is not a practical/socially acceptable option in Chinese. The first, 喷 "erupt", is not exactly common either but is at least used in a few other compounds like 喷水 "fountain".