Definition from Wiktionary, the free dictionary
- A sport resembling tightrope walking but with the rope or webbing only partially taut.
2008 March 14, JerLongman, “900 Feet Up With Nowhere to Go but Down”, New York Times:
- Highlining was a high-wire version of slacklining, an extreme cousin of tightrope walking in which no pole was used for balance and the rope was elastic, allowing for various tricks involving walking, sitting, lying down, flipping, even spinning hula hoops.
- Present participle of slackline.