 This species can only be distinguished from its near relation, "Gastrolobium oxylobiodes", when the species are in flower.The species was formally described in 1955 by the state's botanist C.A.Gardner in "New Species of Toxic Plants from Western Australia", published in The Western Australian Naturalist.The epithet of the botanical name is from the Latin "propinquus" (closely connected), is a reference to the close relationship of the species with "Gastrolobium oxylobiodes".