Alopia nixa is a species of small, tropical, air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Clausiliidae.

On the body whorl, especially near the aperture, these lines transition into dense, fairly strong, yet slightly uneven ribbed streaks.

The slightly convex spire consists of 8.5 flatly rounded whorls, separated by a shallow suture.

The body whorl rises very little or not at all at the front and is somewhat compressed into a weak basal keel around the umbilical slit.

The pear-shaped aperture recedes slightly at the bottom, with a fairly wide, angular sinulus that is barely raised.