The holotype (SAM-PK-K 10369), found in the Tropidostoma Assemblage Zone of the Teekloof Formation, is made up of a crushed skull, partial lower jaw and one leg.

It was named for a notch on its coronoid process which most likely was the insertion point for a chewing muscle, the adductor mandibulae externus.

Since the body of Charassognathus has not been discovered, its full length remains unknown, but estimates have been made at 50 centimetres (20 in).

Charassognathus has a snout that makes up slightly less than half of the total length of its skull and a long facial process on its septomaxilla.

The odd shape of its septomaxilla is more typical of therocephalians than other cynodonts indicating that it may be close to a common ancestor between the two groups.