Swainsona villosa is a prostrate or ascending plant up to about high with many stems, often with their bases below the surface of the soil. The leaves are imparipinnate, mostly long with 7 to 15 egg-shaped leaflets with the narrower end towards the base, the side leaflets long and wide with broad,
stipules long, often with a long tapering tip, at the base of the
petioles. The flowers are usually purple, sometimes pink or white, arranged in racemes of 2 to 15, on a
peduncle about wide, each flower long on a dark, hairy
pedicel long. The
sepals are joined at the base to form a tube about long, with teeth often twice as long as the tube. The
standard petal is long and wide, the
wings long and the
keel long and deep. Flowering mainly occurs from July to August, and the fruit is an oblong to almost spherical
pod long and wide with the remains of the
style long. ==Taxonomy and naming==