As used in the scriptures, to covet is to envy someone or to have an excessive desire for something.
Thou shalt not covet thine own property, D&C 19: 26.
Now there is a thought!
And the example it takes you to is:
Acts 5
1 But a certain man named Ananias, with Sapphira his wife, sold a possession,
2 And kept back part of the price, his wife also being privy to it, and brought a certain part, and laid it at the apostles’ feet.
3 But Peter said, Ananias, why hath Satan filled thine heart to lie to the Holy Ghost, and to keep back part of the price of the land?
4 Whiles it remained, was it not thine own? and after it was sold, was it not in thine own power? why hast thou conceived this thing in thine heart? thou hast not lied unto men, but unto God.
5 And Ananias hearing these words fell down, and gave up the ghost: and great fear came on all them that heard these things.
6 And the young men arose, wound him up, and carried him out, and buried him.
7 And it was about the space of three hours after, when his wife, not knowing what was done, came in.
8 And Peter answered unto her, Tell me whether ye sold the land for so much? And she said, Yea, for so much.
9 Then Peter said unto her, How is it that ye have agreed together to tempt the Spirit of the Lord? behold, the feet of them which have buried thy husband are at the door, and shall carry thee out.
10 Then fell she down straightway at his feet, and yielded up the ghost: and the young men came in, and found her dead, and, carrying her forth, buried her by her husband.
11 And great fear came upon all the church, and upon as many as heard these things.