What is another word for most returnless?
Pronunciation: [mˈə͡ʊst ɹɪtˈɜːnləs] (IPA) 
One possible synonym for "most returnless" could be "irretrievable," which conveys the sense that something cannot be regained or recovered. Other synonyms might include "irrecoverable," "lost," "irremediable," "unrecoverable," "unredeemable," or "beyond recall." Depending on the context, other words like "fruitless," "futile," or "hopeless" might also capture the sense of something being unable to yield any returns or benefits. Whether used to describe a lost investment or a missed opportunity, these synonyms highlight the finality and permanence of the loss, emphasizing that whatever was lost cannot be reclaimed or restored.
