To propel a boat by laying hold of bushes and overhanging branches, and walking toward the stern.
1826. We began to pull the boat up the stream, by a process, which, in the technics of the boatmen, is called bush-whacking.T. Flint, Recollections, p. 86.
1854. When the waters are high, and the boat can run along under bushes on the river-bank, pulling up by the bushes, this is called bush-whacking.Lambert Lilly, History of the Western States, p. 30 (Boston).