馬上

From 馬背上 (mǎ bèi shàng), "on horseback", by extension, "at once; immediately", on account of the horse being the fastest mode of transportation in ancient times.^[1]

馬上

1. at once; immediately; without delay; in a minute; soon

   我馬上就回來。／我马上就回来。  ―  Wǒ mǎshàng jiù huílái.  ―  I'll be back in a minute.

   馬上要過年了，回去又要拼酒了。 [MSC, trad.]
   马上要过年了，回去又要拼酒了。 [MSC, simp.]

   Mǎshàng yào guònián le, huíqù yòu yào pīnjiǔ le. [Pinyin]

   Chinese New Year is coming soon, and I have to have drinking contests again when I go back.

2. (literally and literary) on horseback

   • 馬上相逢無紙筆，憑君傳語報平安。 [Literary Chinese, trad.]
     马上相逢无纸笔，凭君传语报平安。 [Literary Chinese, simp.]

     From: c. 749, Cen Shen, Coming Across a Messenger Going Towards the Capital（《逢入京使》）, translated by Tang Yihe

     Mǎshàng xiāngféng wú zhǐbǐ, píng jūn chuányǔ bào píng'ān. [Pinyin]

     I meet with you on horseback
     With no paper and brush to write.
     Please bring a word to my folks:
     I'm quite well and all right.

   • 馬上幾多時，夢中無限事。 [Literary Chinese, trad.]
     马上几多时，梦中无限事。 [Literary Chinese, simp.]

     From: c. 822, Bai Juyi（白居易）,《自秦望赴五松驛，馬上偶睡，睡覺成吟》, translated as Sleeping on Horseback by Arthur Waley, 1919.

     Mǎshàng jǐduō shí, mèngzhōng wúxiàn shì. [Pinyin]

     For these few steps that my horse had carried me
     Had taken in my dream countless aeons of time!

• (at once):

• 趕快／赶快 (gǎnkuài)

• “馬上”, in 教育部臺灣台語常用詞辭典 [Dictionary of Frequently-Used Taiwanese Taigi] (overall work in Mandarin and Hokkien), Ministry of Education, R.O.C., 2025.

馬(ば)上(じょう) • (bajō) 

1. horseback, the back of a horse
2. horseback riding

• 2002, Ineko Kondō; Fumi Takano; Mary E Althaus; et. al., Shogakukan Progressive Japanese-English Dictionary, Third Edition, Tokyo: Shōgakukan, →ISBN.
• Shinmura, Izuru, editor (1998), 広辞苑 [Kōjien] (in Japanese), Fifth edition, Tokyo: Iwanami Shoten, →ISBN
• Kitahara, Yasuo, editor (2002), 明鏡国語辞典 [Meikyō Kokugo Jiten] (in Japanese), First edition, Tokyo: Taishūkan Shoten, →ISBN