As nouns the difference between heel and coward
is that
heel is (anatomy) the rear part of the foot, where it joins the leg or
heel can be the act of inclining or canting from a vertical position; a cant while
coward is a person who lacks courage.
As a verb heel
is to follow at somebody's heels; to chase closely or
heel can be to incline to one side, to tilt (especially of ships).
As a adjective coward is
cowardly.