"Spoof" as a noun is defined in Microsoft Encarta 2002 as:
hoax: a good-humored hoax
amusing satire: a light amusing satire
The verb tense is defined like this:
deceive: to fool or deceive somebody
satirize: to satirize somebody or something good-naturedly
The term was originally coined by the English comedian Arthur Roberts in the late nineteenth century as the name for a game he created involving hoaxing. However, in the context of network security, spoofing does not involve good humor and good nature, and the definition that is closest to actual use in the context of network security would be to deceive. Spoofing attacks are frequently quite malevolent.
One of the earlier references to security spoofing can be found in an article ...