Shell up to 7.20 mm wide, strongly depressed, thin, highly polished, umbilicate; spire up to about as high as aperture. Uniformly translucent nacreous white.
Protoconch of 1 convex whorl; surface mostly etched away, but remaining areas smooth; diameter 320-330 µm.
Teleoconch of up to 5 regularly expanding whorls; spire outline slightly convex; periphery very sharply angulate, flange-like, its sides slightly concave; base shallowly convex. Spire whorls smooth; first 1.5 whorls shallowly convex, with a low supramedian angulation; subsequent whorls more or less flat. Base smooth apart from a fine spiral thread, itself smooth, at umbilical rim. Umbilicus perspective to protoconch; wall smooth, vertical; diameter up to 28% of shell diameter. Aperture subrhomboidal. Outer lip thin at rim, simple within; posterior and basal notches shallow, broad; depth of posterior notch up to 7,6% of shell diameter; no peripheral notch. Parietal glaze very thin. Inner lip thin, simple, orthocline.

In comparison with Fluxinella discula (Dall, 1889) and F. vitrea (Okutani, 1968), which it very closely resembles, F. lepida is smaller (diameter of 5th whorl 4.00-4.24 mm, cf. 5.30 mm for discula and 6.60 mm for vitrea) and has a more sharply defined shoulder angulation on the first teleoconch whorl. It differs further from F. vitrea in having a vertical umbilical wall (cf. inwardly tapering). Another closely related species, F. lenticulosa n.sp., is described below.

Holotype (NZOI H.378) and 1 paratype (NMNZ), P939 (41°20.4'S, 166°54.8'E), Tasman Basin, alive in foraminiferal ooze, 1760-1799 m, 22 April 1980, r.v. Tangaroa; 3 paratypes, P941 (41°15.2'S, 167°07.2'E), Tasman Basin, alive in foraminiferal ooze, 1463-1457 m, 23 April 1980, r.v. Tangaroa (NZOI).