Millettia pinnata is a legume tree that grows to about 15–25 meters in height with a large canopy which spreads equally wide. It may be deciduous for short periods. It has a straight or crooked trunk, 50–80 centimetres 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 inflorescence bears two to four flowers which are strongly fragrant and grow to be 15–18 millimetres long. The calyx of the flowers is bell-shaped and truncate, while the corolla is a rounded ovate shape with basal auricles and often with a central blotch of green colour.