1. 一方的；单边的；单方面的
A unilateral decision or action is taken by only one of the groups, organizations, or countries that are involved in a particular situation, without the agreement of the others.

1. involving only one part or side

e.g. unilateral paralysis
a unilateral decision

Synonym: one-sided

2. tracing descent from either the paternal or the maternal line only