buff – n. a person who is very interested in something and who knows a lot about it
wild-goose chase – n. a foolish and hopeless pursuit of something unattainable.
eat out of house and home – idiomatic expression : to eat everything that someone has in the house
lie low – phrase keep out of sight; avoid detection or attention
It’s all Greek to me. – idiom : used to mean that you do not understand something
jealousy – n. an unhappy or angry feeling of wanting to have what someone else has
green-eyed monster – n. jealousy thought of as a monster that bites or attacks people
be-all and end-all – n. the most important part of something or the reason for something