What is "to tread upon one's heels"

Heel \Heel\, n. [OE. hele, heele, AS. h[=e]la, perh. for h[=o]hila, fr. AS. h[=o]h heel (cf. Hough); but cf. D. hiel, OFries. heila, h[=e]la, Icel. h[ae]ll, Dan. h[ae]l, Sw. h["a]l, and L. calx. [root]12. Cf. Inculcate.]

1. The hinder part of the foot; sometimes, the whole foot; -- in man or quadrupeds.

   He [the stag] calls to mind his strength and then his speed, His winged heels and then his armed head.
   --Denham.

2. The hinder part of any covering for the foot, as of a shoe, sock, etc.; specif., a solid part projecting downward from the hinder part of the sole of a boot or shoe.

3. The latter or remaining part of anything; the closing or concluding part. ``The heel of a hunt.''
   --A. Trollope. ``The heel of the white loaf.''
   --Sir W. Scott.

4. Anything regarded as like a human heel in shape; a protuberance; a knob.

5. The part of a thing corresponding in position to the human heel; the lower part, or part on which a thing rests; especially:

   1. (Naut.) The after end of a ship's keel.

   2. (Naut.) The lower end of a mast, a boom, the bowsprit, the sternpost, etc.

   3. (Mil.) In a small arm, the corner of the but which is upwards in the firing position.

   4. (Mil.) The uppermost part of the blade of a sword, next to the hilt.

   5. The part of any tool next the tang or handle; as, the heel of a scythe.

6. (Man.) Management by the heel, especially the spurred heel; as, the horse understands the heel well.

7. (Arch.)

   1. The lower end of a timber in a frame, as a post or rafter. In the United States, specif., the obtuse angle of the lower end of a rafter set sloping.

   2. A cyma reversa; -- so called by workmen.
      --Gwilt.

8. (Golf) The part of the face of the club head nearest the shaft.

9. In a carding machine, the part of a flat nearest the cylinder.

   Heel chain (Naut.), a chain passing from the bowsprit cap around the heel of the jib boom.

   Heel plate, the butt plate of a gun.

   Heel of a rafter. (Arch.) See Heel, n., 7.

   Heel ring, a ring for fastening a scythe blade to the snath.

   Neck and heels, the whole body. (Colloq.)

   To be at the heels of, to pursue closely; to follow hard; as, hungry want is at my heels.
   --Otway.

   To be down at the heel, to be slovenly or in a poor plight.

   To be out at the heels, to have on stockings that are worn out; hence, to be shabby, or in a poor plight.
   --Shak.

   To cool the heels. See under Cool.

   To go heels over head, to turn over so as to bring the heels uppermost; hence, to move in a inconsiderate, or rash, manner.

   To have the heels of, to outrun.

   To lay by the heels, to fetter; to shackle; to imprison.
   --Shak.
   --Addison.

   To show the heels, to flee; to run from.

   To take to the heels, to flee; to betake to flight.

   To throw up another's heels, to trip him.
   --Bunyan.

   To tread upon one's heels, to follow closely.
   --Shak.