not identical on both sides of a central line; unsymmetrical; lacking symmetry

Most faces are asymmetric.

(of a logical or mathematical relation) holding true of members of a class in one order but not in the opposite order, as in the relation being an ancestor of.

Chemistry .

having an unsymmetrical arrangement of atoms in a molecule.

noting a carbon atom bonded to four different atoms or groups.

(of a polymer) noting an atom or group that is within a polymer chain and is bonded to two different atoms or groups that are external to the chain.

adjective

awry , crooked , disproportional , gibbous , lacking correspondence , not proportionate , not uniform , unbalanced , unequal , unsymmetrical , asymmetric