/flat"foot'/ or, for 1, /-foot"/ , n. , pl. flatfeet for 1, flatfoots for 2, 3.
1. Pathol.
a. a condition in which the arch of the foot is flattened so that the entire sole rests upon the ground.
b. Also, flat foot . a foot with such an arch.
2. Slang. a police officer; cop.
3. Older Slang. a sailor.
[ 1865-70; FLAT 1 + FOOT ]