Phonetic transliteration of the Italian surname 'Guardi' (gwar-dee). The most famous bearer is Francesco Guardi (1712-1793), the Venetian vedute painter who, with Canaletto, defined the genre of Venetian cityscape painting.
瓜 (guā, 'melon') is the standard 'Gua-' character;
尔迪 (ěrdí) renders the '-ardi' ending.