A Security

1. (uncountable) The condition of not being threatened, especially physically, psychologically, emotionally, or financially.
2. (countable) Something that secures.
3. An organization or department responsible for providing security by enforcing laws, rules, and regulations as well as maintaining order.
4. (law) Something that secures the fulfillment of an obligation or law.
5. (law) Freedom from apprehension.
6. (finance, often used in plural) A tradeable financial asset, such as a share of stock.W
7. (finance) Proof of ownership of stocks, bonds or other investment instruments.
8. (finance) Property etc. temporarily relinquished to guarantee repayment of a loan.
9. A guarantee.
10. (obsolete) Carelessness; negligence.

(condition of not being threatened): safety

(something that secures): protection

(something that secures the fulfillment of an obligation): guarantee, surety

insecurity (condition of being threatened)