flat-footed /ˈflætˌfʊtəd/ adjective Learner's definition of FLAT-FOOTED
1
a : having flat feet平足的;扁平足的 b : walking or moving in a slow and awkward way(行动)笨重的,笨拙的 2
chiefly US, informal : not ready or prepared无准备的 —
usually used in the phrase catch flat-footed通常用于短语catch flat-footed