a type of jealousy in which a person fears the loss of a valued relationship to a rival even though the person's partner has not misbehaved and there is no factual basis for this worry. Jealousy is a feeling of being threatened by or envious of someone else's romantic or sexual relationships. It can be a sign of insecurity or a lack of self-confidence. Jealousy can make you feel like you are losing control of your life and make you feel like you can't trust or be close to the person you are jealous of. It can also make you feel like you can't relax and enjoy your own life.