Question

which definition of envy is being used in the sentence? her envy for her sister’s necklace was obvious to everyone.

Explanation:

In this sentence, "envy" refers to a feeling of discontent or resentful longing aroused by someone else's possessions, qualities, or luck—specifically, the resentment the subject feels toward her sister's desirable necklace, which is noticeable to others.

Answer:

Envy here means a resentful longing for someone else's possession (her sister's necklace), a feeling of discontent at another's good fortune that is obvious to others.