What many cookies are

• Some cookies
• Computer security threat
• Invasive programs
• Some malicious programs
• Programs that track users
• Computer security concern
• Invasive computer program

Wiktionary Word definitions in Wiktionary
n. (context Internet English) programs that surreptitiously monitor and report the actions of a computer user.

Wikipedia Word definitions in Wikipedia
Spyware is software that aims to gather information about a person or organization without their knowledge and that may send such information to another entity without the consumer's consent, or that asserts control over a computer without the consumer's ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
by 2000, from spy + ending from software in the computer sense.