Definition of "go-ahead"

Though Pietas has a combination of features that make terraforming a possibility, the rights to the planet have been tied up in Citadel Council courts for the past eight years. The running joke is that by the time the Council finally gives the go-ahead to colonize the planet, Pietas will have evolved life of its own.

2010, BioWare, Mass Effect 2 (Science Fiction), Redwood City: Electronic Arts, PC, scene: Pietas

Greenwood's time as TSC [Transport Select Committee] chairman came to an end late last year, when MPs finally gave the go-ahead to an early General Election so that the Brexit deadlock in Parliament could be broken.

2020 June 3, Lilian Greenwood talks to Paul Stephen, “Rail's 'underlying challenges' remain”, in Rail, page 34

This turbulent ruler was a very go-ahead monarch indeed. He organised a splendid army, well-drilled and well-equipped with modern arms

1906, Arthur Lincoln Haydon, The Book of the V. C., page 150

"The Sultan's go-ahead, modern in some of his views."

1959, Anthony Burgess, Beds in the East (The Malayan Trilogy), published 1972, page 587