Go-ahead noun – An ambitious person who eagerly goes after what is desired. High-octane and go-ahead are semantically related. In some cases you can use "High-octane" instead an adjective phrase "Go-ahead".
High-octane adjective – Used of gasoline; having a high octane number. Go-ahead and high-octane are semantically related. You can use "Go-ahead" instead an adjective phrase "High-octane".