1†v. shoot at from ambush; attack in a stealthy, unfair manner.
1912  "You laid among the trees an' bushwhacked him. A short shot."
1959  Following their usual pattern of trying to bushwhack any and all locals where Mine Mill is established . . . [they] found themselves in a blind alley. . . .
2†v. prowl about the bush, as a hunter does for game.
1956  I've got a number of surveying jobs for you--they piled up while you were bushwhacking up the river.