Canavalia pubescens is a perennial climbing plant with twining branches. It has compound, alternate leaves with leaflets that are broadly elliptic to suborbicular, elliptic-ovate, or sometimes elliptic-obovate, measuring 2.3–8(–10.2) cm in length and 1.8–5(–7.6) cm in width. The apex of these leaflets is rounded to short-acuminate or mucronate, and the base is broadly cuneate to rounded. The upper surfaces of the leaflets are moderately to sparsely pubescent, especially along the nerves, while the lower surfaces are densely pubescent. The flowers are papilionaceous (resembling a butterfly), usually arranged in 8–20 per axillary pseudoraceme, measuring 3–5 cm long. The calyx is 18–25 mm long, densely pubescent, bilabiate, and 5-lobed, with the upper lip large and the lower lip trifid. The corolla is dark red to pink, with a white spot and streaks toward the base, and the stamens are 10 in number, with one distinct at the base and the rest forming a tube. The ovary is superior, stipitate, with 5–20 ovules; the style is incurved and glabrous; the stigma is small and terminal. The fruit is a compressed pod, 12–18 cm long and 2.5–3.2 cm wide, with appressed pubescence that becomes less prominent in older pods. The seeds are brown to dark reddish brown, oblong-elliptic, and strongly compressed, measuring 15–16 mm in length and 10–11 mm in width, with a long hilum. It is found in open dry sites such as lava fields, kiawe thickets, and dry forests at elevations ranging from 15-540 meters.