Shell heavy, medium length, 19 mm, width +/- 8 mm, high spire. Protoconch broken off. 9 teleoconch whorls. Suture distinct, slightly irregular. Whorls convex with strong, broad axial ribs which tend to join on adjacent whorls, extend suture to suture and well down body whorl, 10 on body whorl, 9 on penultimate whorl. Ribs low just below upper suture, decrease, then become largest at middle of whorl. Crossed by numerous fine spiral lirae which become thickest across middle of whorl and form spiral cords. About 20 cords on body whorl extend to anterior tip of shell. Outer lip thickened into varix, incurved. Sinus on shoulder, deep U shaped, slightly constricted at entrance by strong callus. Columella of moderate width, margin pronounced. Aperture deep, glossy white. Anterior canal short, broad, deep, anterior of shell truncate. Shell a uniform chalky white with small light brownish patches on the upper parts of the first six axial ribs on the body whorl.

This species was recognized as new by Dr. A. W. B. Powell and a draft description was written his manuscript "Turridae, Subfamily Clavinae of the lndo-Pacific" which he intended for publication as part of his series in Indo-Pacific Mollusca. Unfortunately the paper was never published. According to Powell's manuscript, Clavus occiduus resembles the Indian Pleurotoma aglaia Dall, 1918 and P. crassa Smith, 1888 which Powell considered to be synonymous. He considered C. occiduus to be smaller, with a shorter spire, distinct subsutural marginal cord, narrower and deeper shoulder sulcus, and crisper sculpture.

Type locality: Central bank, Roebuck Bay, Broome, Western Australia. Distribution:
Known only from the type locality.