Shell slender fusiforme, rather thin, semitransparent, with 4,5-5,5 adult whorls, that are slightly convex to subcylindrical with their greatest convexity just below the upper suture. The apex consists of about one and a half whorl(s) which are completely smooth and «peg-like»; the transition to the adult stage is marked by several narrow closely spaced brephic axials. Sculpture of narrow axial ribs, nearly straight and inclined to the right, numbering 0-10 on the body whorl; these ribs extend to the base of the shell as well as to the suture; the whole surface is covered by numerous microscopical spiral striae passing over the ribs; some of these striae are somewhat stronger; this type of spiral sculpture is also found in the species Mangelia rugulosa and Mangelia coerulans (PHILIPPI, 1844); the last species is closely related to M. secreta. Colour glossy white, with a more or less strongly buff-coloured spiral band on the bodywhorl; the lower limit of this band is found at about the same level as the top of the mouth; on the upper whorls part of this band can be seen just above the lower suture; the interstices between the axial ribs are tinged brown near the upper suture. Suture clearly marked, but not very deep, undulated by the axial ribs. Mouth somewhat expanded, occupying somewhat less than half the total length. Outer lip strengthened by a labial varix at the outside, only slight-ly notched. Canal short, rather wide, unnotched; Inner lip smooth.
Measures: 6.9 - 11 mm x 3.0 x 4 mm; average: 8.5 x 3.3 mm.