Jealousy
The fear and anguish of losing a valued relationship to a rival.
What it means
Jealousy is the complex, often turbulent emotion arising from the perceived threat of losing a valued relationship, especially a romantic one, to a real or imagined rival. It is crucially distinct from envy, with which it is often confused: jealousy is a three-party situation—self, partner, and rival—centered on protecting something one already has, whereas envy is a two-party situation centered on wanting something another person possesses. Jealousy blends several feelings, including fear of loss, anger at the threat, anxiety, and wounded self-esteem, and it motivates a range of behaviors from vigilance and reassurance-seeking to controlling or aggressive 'mate-guarding.' Evolutionary accounts treat it as a guarding mechanism that protects valued bonds and reproductive interests, and some research reports sex differences in whether sexual or emotional infidelity is found more distressing, though this is debated. Mild jealousy can signal investment, but intense or chronic jealousy corrodes trust and is implicated in relationship conflict and violence. It matters because it is a powerful, common force shaping intimate relationships and social bonds.
Examples
Seeing a partner laughing closely with an attractive stranger, a person feels a rush of fear, anger, and insecurity and grows watchful or possessive—jealousy, not envy.
A child watches his mother read the bedtime story to the new baby and turns clingy and cross — he is not coveting the baby, he is guarding a bond he already had.
Your closest friend starts spending every weekend with a new colleague, and the ache is about losing the friendship, not about wanting anything the colleague has.