D defs.my
Entry 6 senses Webster, 1913

Flat-footed

· Flat·-foot·ed · IPA /ˈflætˌfʊtəd/
01 a. Having a flat foot, with little or no arch of the instep; suffering from fallen arches.
  1. 1.
    Having a flat foot, with little or no arch of the instep; suffering from fallen arches.
  2. 2.
    Firm-footed; determined.[Slang, U.S.]
  3. 3.
    clumsy; amateurish; pedestrian; unimaginative; plodding; as, flatfooted prose.
  4. 4.
    Without reservation; without evasion or compromise; firm; as, a flat-footed refusal; a flatfooted denial.
  5. 5.
    With feet flat on the ground; not tiptoe.
  6. 6.
    Unprepared and unable to react quickly; as, the new product caught their competitors flat-footed.
Phrases & compounds
To catch (one) flatfooted — to catch (a person) unprepared; to catch (a person) by surprise.