globalcommonly used in United States and United Kingdompoliticalrhetorical
A warning that if people or governments respond to terrorist acts by abandoning core values, yielding to fear, changing policy, or conceding objectives, then the terrorists will have achieved their desired outcome.
A rhetorical claim used to justify continued resistance, non-capitulation, or the maintenance of normal behavior in the face of terror, on the grounds that otherwise the attackers' goals are realized.
2.
globalinformalcolloquial
A hyperbolic expression used more generally to suggest that conceding to any coercive or fear-inducing demand means that the coercer has succeeded.
Examples:
EN: If we don't do our part, the terrorists will have won.
ES: Si no hacemos nuestra parte, los terroristas habrán ganado. Vamos, Alison.
ID: Jika kita tidak melakukan bagian kita, para teroris akan menang.
EN: If we leave, the terrorists will have won.
HI: अगर वे जाते हैं तो आतंकियों का मकसद सफल होगा.
EN: Again, it's "Surely the terrorists will have won."