Green’s Dictionary of Slang

knowledge, ability; thus rumgumptious adj,, knowing, positive, blunt, pert.

1768		A. Ross Helenore in Wattie Scot. Works (1938) 7: They need not try thy jokes to fathom, / They want rumgumption.
1785		Grose Classical Dict. of the Vulgar Tongue n.p.: Gumption, or rum gumption, docility, comprehension, capacity.
1812		J. Bell Jr. (ed.) Rhymes of Northern Bards 316: Aw know that Cockneys crake rum-gum-shus chimes.
1819		‘One of the Fancy’ Tom Crib’s Memorial to Congress 3: Has thought of a plan, which – excuse his presumption – / He hereby submits to your Royal rumgumption. [...] Gumption or Rumgumption, comprehension, capacity.
1822		J. Hogg Three Perils of Man I 78: Ye sud hae stayed at hame, an’ wantit a wife till ye gathered mair rummelgumption [F&H].
1846		Elgin Courier (Moray, Scot.) 27 Feb. 2/2: I dinna profess [...] to hae the rumgumption needit to fully expound knotty subjects.
1856		Elgin Courant 4 Apr. 6/3: I hardly ever kent a bonny man wi’ common rumgumption.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1862		Elgin Courant 10 Oct. 6/3: Some o’ them [...] slip intae oor Parliament wha hinna sae muckle naitral rumgumption i’thers as my Eppie needs tae set her moose trap.
1864, 1867, 1870		Hotten Sl. Dict.
1877		‘Canny Newcassel’ in Laughing Songster 108: Aw knaw that the cockneys crack rum-gum-shus chimes.
1885		Aberdeen Jrnl 20 Feb. 3/6: It disna need grite rumgumption t’ fin’t oot.
1893		Burnley Exp. 5 Aug. 2/7: I suppose ye’ll credit me wi’ some little bit o’ rumgumption.
1895		C. Crowe Aus. Sl. Dict. 68: Rumgumption, knowledge, wide-awake, etc [...] Rumgumptious, haughty; pugilistic.
1913		Aberdeen Jrnl 18 June 6/4: The comparisons he made [...] demonstrated, if he only had the rumgumption to see it, the fallacy of his contentions.
1924		Aberdeen Jrnl 31 May 5/2: I hae ettled at the Author’s Meaning as near as my sma’ Rumgumption cou’d guess.