Green’s Dictionary of Slang

high-octane adj.

[SE high octane, of gasoline; cf. low-octane under low adj.]

1. dynamic, high-powered.

[Can]Maclean’s (Toronto) 11 Feb. 22: Last year’s high-octane effort to woo workers had only limited success [HDAS].
[US]Calif. Feb. 36: Sustained, high-octane acting is beyond him [HDAS].
Anchorage Daily News [Internet] Nugent’s profane, high-octane politics stoked the crowd, which came back with hoots, laughs and even an ‘Amen!’.

2. of alcohol and drugs, highly intoxicating.

BeerAdvocate [Internet] High octane brew, aimed for people that want a quick and ugly buzz.
[Aus]J. Birmingham Tasmanian Babes Fiasco (1998) 181: Gobbling down fistfuls of high octane drugs.
Sonoma County Indep. 2–8 Oct. [Internet] Often referred to on the street as ‘liquid crack,’ malt liquor is the dregs of American brews. [...] Even beer industry papers refer to malt liquor as ‘high octane’.

3. of coffee, strong, highly caffeinated.

[US]T. Hillerman Sacred Clowns 77: I’m out of decaf. And you shouldn’t be drinking the high octane stuff this late.
Phila. City Paper [Internet] The variety of high-octane coffee drinks can be fun for a rush.