Definition of Fishing trip or expedition
Using the courts to find out information beyond the fair scope of the lawsuit. The loose, vague, unfocused questioning of a witness or the overly broad use of the discovery process. Discovery sought on general, loose, and vague allegations, or on suspicion, surmise, or vague guesses. The scope of discovery may be restricted by protective orders as provided for by Fed.Rule Civil P. 26(c).
That's the definition of Fishing trip or expedition in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.