Dimethicone, also known as polydimethylsiloxane, is a silicon-based polymer that is a man-made synthetic molecule made up of repeating units called monomers. Silicon is the second most abundant element in the Earth's crust after oxygen, and silicon dioxide is also known as sand, commonly found on beaches and shores.
In regards to a job, a refusal letter is written when a company offers a position to an individual who must refuse due to his or her circumstances, such as already having accepted another offer, or simply a lack of interest in this particular job.
A poison pen letter is a letter or note containing unpleasant, abusive or malicious statements or accusations about the recipient or a third party. It is usually sent anonymously. In the term poison pen, the word poison is used figuratively, rather than literally. Poison pen letters are usually composed and sent to upset the recipient. They differ from blackmail, which is intended to obtain something from the recipient. In contrast, poison pen letters are purely malicious.