type of alcoholic drink, 1898, probably from ball "drink of whiskey;" high because it is served in a tall glass.
To speed; rush: A train was thirty yards away, highballing down the track/ One New York distributor highballed 30 trucks through the Holland Tunnel (1925+ Railroad)
[fr the former use of a railroad trackside signal using a two-foot globe, raised or lowered, to instruct the engineer; the military sense fr the use of a railroad conductor's raised hand or fist as a signal to the engineer to start, the term transferred from the mechanical signal; the drinking sense is probably fr a ball, ''drink of whiskey'' in a high glass]