What is the meaning of envy (Hasad) in Islamic law?

Envy, linguistically, is wishing for the disappearance of a blessing from the envied person. Legally, it is broader than that, and it has four levels: 1. Wishing for the disappearance of the blessing from the envied person without it transferring to the envious person (very malicious). 2. Wishing for the disappearance of the blessing from the envied person and its transfer to the envious person (reprehensible). 3. Wishing for a similar blessing, and if unable to attain it, wishing for its disappearance so that the disparity does not become apparent (contains both reprehensible and non-reprehensible aspects). 4. Ghibtah (admirable emulation): Wishing for a similar blessing without wishing for its disappearance if it is not attained (excused in worldly matters, and religiously recommended).

The first and second levels are absolutely reprehensible. Naming ghibtah as envy is a figurative use of the word.