Gonystylus eximius is a tree in the family Thymelaeaceae. The specific epithet eximius means 'excellent'.
Gonystylus eximius grows as a small tree up to tall, with a stem diameter of up to . The twigs are yellowish brown. Its flowers are reddish brown.
Gonystylus eximius is endemic to Borneo, where it is known only from Sarawak. Its habitat is lowland mixed dipterocarp forest at altitudes of .