Jealousy typically refers to the thoughts, feelings, and behaviors that occur when a person believes a valued relationship is being threatened by a rival. This rival may or may not know that he or she is perceived as a threat.
Parrott makes use of the cause of jealousy to define it: “jealousy is an emotion experienced when a person is threatened by the loss of an important relation with another person” (Parrot, 2001, p. 313). He further defines it also as “a type of anxious insecurity following from the perception of threat to a relation” which sustains the jealous’ self (Parrot, 2001, p. 314). Prinz (2004, p. 93) says that jealousy is a “non basic emotion”, meaning that “it is combination of basic emotions with other mental states that are not emotions”. His statement has a foundation on the concept of basic and non basic emotions, which he takes from Plutchik. Prinz (2004, p. 93) suggests that jealousy “contains anger, sadness, disgust” (basic emotions), “all brought together by the belief that one’s lover has been unfaithful” (mental state). Further, Goldie says jealousy is a passion, focusing his definition on the effects of jealousy, which “frequently get out of control” (2000, p. 229). It is a common observation that the experience of jealousy can last much longer than the one of a basic emotion like anger, without losing its original intensity, and, in a paradox captured in Rochefoucauld's maxim, it may outlast the attachment which it fears losing: "jealousy is always born with love; it does not always die with it."