A jerk or involuntary muscular contraction resulting from a smart tap on the patellar tendon.

【医】膝反射；膝盖键反射。

Automatic; reacting in a readily predictable way.

自然反应的；机械式地反应的。

A person whose reactions are predictable or automatic, especially in politics.

反应可测的人；机械般反应的人(特指在政治方面)。