flat-foot·ed • adj. 1. having flat feet: a flat-footed, overweight cop. 2. having one's feet flat on the ground: he landed with a flat-footed thud | [as adv.] thudding flat-footed through the lane. ∎ inf. unable to move quickly and smoothly; clumsy: getting caught in flat-footed ignorance can be uncomfortable. ∎ inf. not clever or imaginative; uninspired: he has little space for anecdote, but the text is no flat-footed catalog. PHRASES: catch someone flat-footed inf. take someone by surprise: the rise of regional conflicts has caught military planners flat-footed.DERIVATIVES: flat-foot·ed·ly adv. flat-foot·ed·ness n.