In linguistics, converses or relational antonyms are pairs of words that refer to a relationship from opposite points of view, such as parent/child or borrow/lend.^[1][2] The relationship between such words is called a converse relation.^[2] Converses can be understood as a pair of words where one word implies a relationship between two objects, while the other implies the existence of the same relationship when the objects are reversed. ^[3] Converses are sometimes referred to as complementary antonyms because an "either/or" relationship is present between them. One exists only because the other exists.^[4]

• Own and belong are relational opposites i.e. "A owns B" is the same as "B belongs to A."
• Win and lose i.e. if someone wins, someone must lose.
• Fraction and whole i.e. if there is a fraction, there must be a whole.
• Above and below
• Employer and employee
• Parent and child
• Teacher and student
• Buy and sell
• East and west
• Predator and prey
• Lend and borrow
• Offense and defense
• Slave and master

• Opposite (semantics)