Back in the 1970's I began using this word for a few years. I used it more as a replacement for 'dag'.
So if somebody did something funny or stupid, I said they were a bit of a 'goober'.
I came across the word when I was listening to a record single
called 'Goober Peas'.
Forms: Also gouber ( Cent. Dict.).
The peanut, Arachis hypogæa.
1833 Louisville Publ. Advt. 7 Nov., A few bags Gouber Pea, or Ground Pea [for sale].
1834 Cherokee Phoenix (New Echota, Georgia) 24 May 3/4 But he so seam I frade of he,
I guess he steal my goober.
1848 Rep. U.S. Comm. Patents 1847 190 The ground pea of the south, or as it is sometimes called,
the gouber or pindar pea.
1871 M. Schele de Vere Americanisms (1872) 57 The peanuts or earth~nuts known
in North Carolina and the adjoining States as Goober peas, so that during the late Civil War
a conscript from the so-called ‘piney woods’ of that State was apt to be nick-named a Goober.
1885 U.S. Cons. Rep. No. liv. 382 From the handling of our orchard crops to raking goobers
out of the ground, there is probably [etc.].
1887 Boston (Mass.) Jrnl. 31 Dec. 2/4 Hogs that had been fed on acorns and goobers.
1888 Cent. Mag. 36 770/2 Peanuts, known in the vernacular as ‘goobers’.