"Hath dinner" is an outdated phrase that is seldom used nowadays. However, if we were to look for synonyms for the phrase, we could consider options such as 'dined', 'supped', or 'feasted'. These words convey the same meaning as 'hath dinner', but are more commonly used in contemporary English. Other possible synonyms for the phrase could be 'had a meal', 'ate dinner' or 'consumed food'. Regardless of the synonym used, the message remains the same: someone has eaten dinner. It's worth noting that language and phrases evolve over time, and what was once popular may no longer be seen as standard English.