noun
tail end; last person; dead last
Colloquial noun for the person or thing that comes last in a sequence, especially in races, arrivals, or completions. Often used in casual contexts.
See also: どんじり
マラソンでどんじまいになったけど、完走できて嬉しい。
I came in dead last in the marathon, but I'm happy I finished.
彼はいつも飲み会にどんじまいで来る。
He always arrives last to the drinking party.
どんじり is a more common synonym with the same meaning. どんじまい is a rarer variant.
びり also means 'last place' but is more common and neutral. どんじまい has a slightly more colloquial, playful tone.
Likely a compound of どん (emphatic prefix, as in どん底) and しまい (仕舞い, 'end'). The exact derivation is uncertain.