Source : Webster's Revised Unabridged Dictionary (1913)

Clinch \Clinch\ (kl[i^]nch), n.
   1. The act or process of holding fast; that which serves to
      hold fast; a grip; a grasp; a clamp; a holdfast; as, to
      get a good clinch of an antagonist, or of a weapon; to
      secure anything by a clinch.

   2. A pun. --Pope.

   3. (Naut.) A hitch or bend by which a rope is made fast to
      the ring of an anchor, or the breeching of a ship's gun to
      the ringbolts.

Clinch \Clinch\ (kl[i^]nch; 224), v. t. [imp. & p. p.
   {Clinched}; p. pr. & vb. n. {Clinching}.] [OE. clenchen,
   prop. causative of clink to cause to clink, to strike; cf. D.
   klinken to tinkle, rivet. See {Clink}.]
   1. To hold firmly; to hold fast by grasping or embracing
      tightly. ``Clinch the pointed spear.'' --Dryden.

   2. To set closely together; to close tightly; as, to clinch
      the teeth or the first. --Swift.

   3. To bend or turn over the point of (something that has been
      driven through an object), so that it will hold fast; as,
      to clinch a nail.

   4. To make conclusive; to confirm; to establish; as, to
      clinch an argument. --South.

Clinch \Clinch\, v. i.
   To hold fast; to grasp something firmly; to seize or grasp
   one another.

Source : WordNet®

clinch
     n 1: (boxing) the act of one boxer holding onto the other to
          avoid being hit and to rest momentarily
     2: a small slip noose made with seizing [syn: {clench}]
     3: the flattened part of a nail or bolt or rivet
     4: a tight or amorous embrace; "come here and give me a big
        hug" [syn: {hug}, {squeeze}]

clinch
     v 1: secure or fasten by flattening the ends of nails or bolts;
          "The girder was clinched into the wall"
     2: hold a boxing opponent with one or both arms so as to
        prevent punches
     3: hold in a tight grasp; "clench a steering wheel" [syn: {clench}]
     4: embrace amorously
     5: flatten the ends (of nails and rivets); "the nails were
        clinched"
     6: settle conclusively; "clinch a deal"