Distinguishing features include the absence of forelimbs, and replacement of hindlimbs for scaly-flaps, accompanied by snake-like, lidless eyes.

[9] This group of terrestrial legless lizards is characterised by well-developed hindlimb flaps, external ear openings and a broad, rounded tongue.

This clade is a widely geographically distributed group, and diverged from other Delma during the drying out of Australia during the Miocene (~15mya), with rapid speciation occurring between 10mya and 5mya.

The dorsal colouration of this species is grey, grey-brown or olive brown, with specimens often sporting a yellow throat.

[8][13] Delma inornata resembles Pygopus, and their gekkonid relatives, in their invertebrate-heavy diet, rounded head shape, peglike & crushing dentition and low degree of cranial kinesis.

The olive legless lizard has a fully extended, bi-lobed, bulb-shaped hemipenis, with poorly differentiated apical lobes.

[33][36][37][5] The olive legless lizard also occurs in farming and grazing lands, where vegetation is often cleared and therefore sparse (although native & perennial grasses should still dominate).

These populations have adapted to use farming equipment such as water troughs, along with rocks, logs, metal and wooden debris for cover.

[8][5] In southern New South Wales, the olive legless lizard was significantly more likely to be detected in areas with a simple microhabitat structure.

[38][35] Tree plantings appear to have a higher abundance of olive legless lizards than fragmented habitat due to grazing exclusion and the accumulation of leaf litter and tussock-forming grass species which provide suitable cover and foraging potential.

[7][8] At least in the southernly portions of its range, Delma inornata becomes dormant in the winter months, either burying itself up to 30 cm into the soil, or hiding under fallen timber or industrial litter.

[42] They are found to mainly target surface active insects such as grasshoppers and adult butterflies & moths, along with cockroaches, spiders and caterpillars.

Larger prey items (e.g. cockroaches) are killed or immobilized by crushing, violent shaking and beating against the ground.

[13] Breeding occurs in the early summer season, where ideal temperatures remain consistent, although pregnant females have been found in January.

[8] Although present on farming & grazing lands, and willing to tolerate moderate levels of habitat modification by humans, human-related threats include further land clearing and fragmentation, predation by feral animals, use of pesticides, habitat disruption, trampling by sheep & cattle, and humans mistaking Delma inornata for juvenile brown snakes.