The Collaborative International Dictionary of English v.0.48:

Cluck \Cluck\, v. i. [imp. & p. p. Clucked; p pr. & vb. n.
   Clucking.] [AS. cloccian; cf. D. klokken, G. glucken,
   glucksen, LG. klukken, Dan. klukke; all prob. of imitative
   origin.]
   To make the noise, or utter the call, of a brooding hen.
   --Ray.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cluck \Cluck\, v. t.
   To call together, or call to follow, as a hen does her
   chickens.
   [1913 Webster]

         She, poor hen, fond of no second brood,
         Has clucked three to the wars.           --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cluck \Cluck\, n.
   1. The call of a hen to her chickens.
      [1913 Webster]

   2. A click. See 3d Click, 2.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cluck
    n 1: the sound made by a hen (as in calling her chicks) [syn:
         cluck, clucking]
    v 1: make a clucking sounds, characteristic of hens [syn:
         cluck, click, clack]