highball /ˈhaɪˌbɑl/noun 4verb 2forms 3 noun4 •A cocktail made from a spirit plus soda water etc. •Clipping of highball glass, a tall glass tumbler used for serving highballs.It's great for serving heavier drinks in. Highballs and pint glasses are excellent substitutes. — 2021 •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. — 2014 •(US) An all clear or full speed ahead signal. verb2 •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, old-fashioned) To move quickly; to hightail.Booster-equipped 628 highballs west at Glen Lake, Minn., back in 1947. — 1959 formshighballed · highballing · highballs