こゆび小指koyubi
1.
The smallest and outermost finger on the hand, counted as the fifth finger from the thumb, often associated with gestures or symbolism related to marital or romantic relationships.
2.
A finger that is commonly used in cultural practices, such as making promises or indicating a spouse or lover through specific hand signs.
3.
The least prominent finger on both hands and feet, which holds a unique role in various gestures or symbols of companionship and fidelity.
Example:
小指がはれました。