Millettia pinnata is a legume tree that grows to about 15–25 m (50–80 ft) in height with a large canopy that spreads equally wide. It may be deciduous for short periods. It has a straight or crooked trunk, 50–80 cm (20–30 in) in diameter, with grey-brown bark, which is smooth or vertically fissured. Branches are glabrous with pale stipulate scars. The imparipinnate leaves of the tree alternate and are short-stalked, rounded, or cuneate at the base, ovate or oblong along the length, obtuse-acuminate at the apex, and not toothed on the edges. They are a soft, shiny burgundy when young, and mature to a glossy, deep green as the season progresses, with prominent veins underneath.
Flowering generally starts after 3–4 years with small clusters of white, purple, and pink flowers blossoming throughout the year. The raceme-like inflorescences bear two to four flowers that are strongly fragrant and grow to be 15–18 mm (0.59–0.71 in) long. The calyx of the flowers is bell-shaped and truncated, while the corolla is a rounded ovate shape with basal auricles and often with a central blotch of green color.