What is Knee-jerk?
1.
A spontaneous, thoughless, predictable and stereotypical reaction to something, usually an opinion or a statement.
An entire culture of American neo-conservatives has seemed to build itself on a type of knee-jerk reaction to any kind of criticism of the Bush Administration or the loyal element of the Republican Party, even from fellow conservatives -- the kind of pseudo-patriotism discouraged by Theodore Roosevelt.
2.
automatic, quick and without thought
Allergies are the immune system's knee-jerk defensive responses to unknown substances.
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