Oops yea Tony is right. I have never heard that lol

I am a native speaker of korean. I have not heard such that term. It could be used like decades ago though. Anyways nobody uses the term these days

I looked it up and it is supposed to be 두 말 가웃, where 두 means two, and 말 가웃 is a unit expression. - 두 말 가웃 = 두(2) + 말(old measure unit = 4.76542 gallons) + 가웃(old suffix for "roughly that much") = about two 말s. 되 (1/10 of 말) and 말 are traditional units for measuring grains ("쌀 두 말", "콩 두 되"), but only some rural farmers might know them these days. 가웃 seems even more obscure - I personally never heard the term.