Source : Webster's Revised Unabridged Dictionary (1913)

Hobnob \Hob"nob`\, adv. [AS. habban to have + habban to have
   not; ne not + habban to have. See {Have}, and cf. {Habnab}.]
   1. Have or have not; -- a familiar invitation to reciprocal
      drinking. --Shak.

   2. At random; hit or miss. (Obs.) --Holinshed.

Hobnob \Hob"nob`\, v. i. [imp. & p. p. {Hornobbed}; p. pr. & vb.
   n. {Hornobbing}.]
   1. To drink familiarly (with another). [ Written also
      {hob-a-nob}.]

   2. To associate familiarly; to be on intimate terms.

Hobnob \Hob"nob`\, n.
   Familiar, social intercourse. --W. Black.

Source : WordNet®

hobnob
     v : rub elbows with; "He hobnobs with the best of society"
     [also: {hobnobbing}, {hobnobbed}]