A scalene triangle has no equal sides. There is no word for a triangle with three different angle sizes. The words describing angle sizes — right, obtuse and acute — reference the degrees of the angle, not their relationships to one another.
A right triangle has one right angle that measures 90 degrees. An obtuse triangle has one angle that is larger than 90 degrees, and all angles of an acute triangle are less than 90 degrees.
Therefore, a scalene triangle can be described using additional terminology. For example, a scalene triangle with sides that are 45, 60 and 75 units in length is an acute scalene triangle. If the angles measure 90, 50 and 40 degrees, it is a right scalene triangle.