"Cupboard love" is an English

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 phrase referring to affection that is given purely to gain a reward.

The term derives from the way in which a cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

 will give a cupboard

Cupboard

A cupboard or press is a type of cabinet, often made of wood, used indoors to store household objects such as food, crockery, textiles and liquor, and protect them from dust,vermin and dirt....

 containing its food superficial "love" (which is not normally exhibited) when it wants to be fed. The phrase is most often applied to human activity, for example when a child will say "I love you so much" before or after requesting a treat, for example an ice cream.

Cupboard love is a milder version of conditional love

Unconditional love

Unconditional love is a term that means to love someone regardless of one's actions or beliefs. It is a concept comparable to true love, a term which is more frequently used to describe love between lovers. By contrast, unconditional love is frequently used to describe love between family members,...

, where love is given solely in response to certain behaviour. Some local authorities class conditional love as a form of emotional abuse.