It has a single thin leaf and up to twenty three dark purplish-black flowers which lean downwards.

The edges of the dorsal sepal are densely hairy, the hairs up to 0.5 mm (0.02 in) long.

There is a purplish-black, tapered callus in the centre of the labellum and covering about half of its surface.

[1][6] The specific epithet (simulans) is a Latin word meaning "imitating" or "copying",[7] referring to the similarity of this species to G.

[3] Genoplesium simulans grows in forest and with mosses in shallow soil over sandstone in the Blue Mountains and south to Mount Keira.