What is "to venture upon"

Venture \Ven"ture\, v. i. [imp. & p. p. Ventured; p. pr. & vb. n. Venturing.]

1. To hazard one's self; to have the courage or presumption to do, undertake, or say something; to dare.
   --Bunyan.

2. To make a venture; to run a hazard or risk; to take the chances.

   Who freights a ship to venture on the seas.
   --J. Dryden, Jr.

   To venture at, or To venture on or To venture upon, to dare to engage in; to attempt without any certainty of success; as, it is rash to venture upon such a project. ``When I venture at the comic style.''
   --Waller.