What is the meaning of Jealous?

Suspecting rivalry in love; troubled by worries that one might have been replaced in someone's affections; suspicious of a lover's or spouse's fidelity.

Protective; zealously guarding; careful in the protection of something (or someone) one has or appreciates, especially one's spouse or lover.

Envious; feeling resentful or angered toward someone for a perceived advantage or success, material or otherwise.

Suspicious; apprehensive.

To harass or attack (somebody) out of jealousy.

To deliberately make (someone) jealous of another person's (often their partner's) associations with other people.

Source: wiktionary.org