百日の説法屁一つ: “a hundred days of sermonizing, one fart” → a metaphor for how extreme effort something that one has put great effort into can come to nothing after even a slight mistake, much as a hundred days of serious spiritual study can be lost to the winds

being newly made / a newly made item

a female given name

cart (small, open, wheeled vehicle used for transporting goods, especially a shopping cart) / go-cart (racing vehicle)