What does "countermeasure" mean?

Any action taken to counteract or correct another.

What is a synonym for "countermeasure"?

Common synonyms include: act against, antido, antidote, antidotes, backfire, chaff.

Pronounced //ˈkaʊntəmɛʒə//.

/ˈkaʊntəmɛʒə/ noun

noun ·Rare ·Advanced level

Noun

1
Any action taken to counteract or correct another.
"We fear that this will be the beginning of a negative development of measures and countermeasures, at the end of which there will be no winner"
2
an action taken to offset another action wordnet
3
Any of the devices and techniques used to impair the operational effectiveness of an enemy. in-plural

"We fear that this will be the beginning of a negative development of measures and countermeasures, at the end of which there will be no winner"

From counter- + measure.