It is a bushy or straggling shrub with asymmetric, narrowly oblong to broadly egg-shaped phyllodes with the narrower end towards the base, flowers arranged in a spherical heads 4.0–4.5 mm (0.16–0.18 in) in diameter with 8 to 20 flowers, and a spirally coiled to twisted pods up to 3.0–4.5 mm (0.12–0.18 in) long.

Acacia acinacea is a bushy or straggling, open shrub that typically grows to a height of around 2.5 m (8 ft 2 in).

The pods are spirally coiled to twisted, 3.0–4.5 mm (0.12–0.18 in) wide and glabrous, with a hard outer surface.

[3][4][5][6][7] The species was first formally described by the botanist John Lindley in 1838 as part of Thomas Mitchell's work Three Expeditions into the interior of Eastern Australia.

[8][9] The specific epithet, acinacea, derives from the Latin for a short Persian sword (acinaces) and references the shape of the phyllodes.