Definition from Wiktionary, the free dictionary
highball (plural highballs)
- A cocktail made from spirit plus soda water etc.
- (rail transport) An all clear or full speed ahead signal.
- (Climbing) A very high bouldering problem, often with a hard landing.
- Austrian all rounder Alex Luger climbs what he describes as a highball boulder problem and what most people would call a solo. — (EpicTV.com, 2014)
- To make an estimate which tends toward exaggeration.
- If we highball the price, it comes out to $240. If we lowball it, it's closer to $200.
- (slang, rare or erroneous) To move quickly; to hightail.
- (estimate): lowball