From {etyl|bnt|en} {m|bnt-pro||ngombo}, {m|bnt-pro||kingombo|okra plant}, possibly via {etyl|gul|en}.[1][2] Cognate to Ŝablono:cog, Caribbean Ŝablono:cog, and cognates in other Romance languages.
The team stuck fast in the black muck, and every effort to extricate them served only to imbed them more hopelessly in the sticky gumbo.
1914 April, "Making Good Roads by Firing Poor Ones," Popular Mechanics, p. 567:
There are no poorer roads in all the United States than the "gumbo" roads of the south—gumbo being the name give a certain kind of mud or clay that is particularly sticky, clings tenaciously, seems to have no bottom, and will not support any weight.