What is the meaning of Flat-footed?

Of an animal: having feet which are naturally flat; of a horse: having hoofs with soles close to the ground.

Of a person: having the physical condition of flat feet (“a condition where the soles of the feet are in full contact with the ground, either because the arches have collapsed or because they never developed”).

Of a thing (especially a rail): having a flat base; flat-bottomed.

1. Blunt and unsubtle; lacking finesse; clumsy.

   Blunt and unsubtle; lacking finesse; clumsy.

   Unprepared, unready.

   Direct, downright, straightforward; also, holding firmly to and maintaining a decision; standing one's ground.

   simple past and past participle of flat-foot.

   Source: wiktionary.org