Kadua acuminata is a scandent or arcuate shrub or subshrub with stems ranging from 2 to 4 m in length. These stems are terete (cylindrical) to quadrangular, sometimes slightly winged, and bear short, glabrous lateral branches spanning 10 to 100 cm. The leaves are simple, opposite, and widely spaced along the stem. They vary in shape from lanceolate to ovate and are sized between 5 to 18 cm long and 1.6 to 8 cm wide. The leaf apex can be acuminate to long-acuminate or occasionally caudate, while the base ranges from cuneate to rounded. The lower surfaces of the leaves are either glabrous or hirtellous, particularly along the veins, and the material of the leaves is firm-chartaceous to subcoriaceous. The leaves have entire margins and slightly to prominently raised lateral veins on the lower surface. Petioles are 0.4 to 4.5 cm long and can be glabrous or hirtellous. The flowers occur singly or up to seven in reduced axillary cymose inflorescences. The flowers are bisexual (perfect) and pistillate, typically pollinated by insects, featuring a nectary disc. The calyx lobes are narrowly lanceolate to narrowly ovate, measuring 5 to 15 mm long. The corolla is yellowish green, occasionally green, with a 7 to 18 mm long salverform structure that enlarges slightly at the throat. Stamens are inserted in the upper part of the corolla tube and alternate with the corolla lobes. The ovary is inferior or partly so, with two to four locules. The fruit is a woody capsule, broadly turbinate to turbinate-globose, and strongly quadrangular or sometimes winged, measuring 6 to 12 mm in length and 5 to 10 mm in diameter. It dehisces loculicidally across the disk with translucent reddish seeds, cuneiform, sharply angled, and minutely reticulate. It inhabits mesic to occasionally wet forests between 90 – 800 meters.