This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. Plural form of countermeasure.

n. All the devices and techniques used to impair the operational effectiveness of an enemy

"The idea that you can tackle unauthorised filesharing by security countermeasures is very attractive, but not accurate."

countermeasure    vulnerabilities    defenses    deterrence    damper    intercept    surveillance    counterattack    encryption    deterrent