(No, that would be 独断線香.)
Literally: alone – sever / decide – exclusive – go / act
Alternately: Deciding what to do, and then doing it, all on one’s own without consulting anybody else. Acting arbitrarily or willfully rather than in accordance with consensus.
Notes: In the US, we place a high value on individualism and decisive action, and our media routinely glorify loners who break away from the pack to do what they think is right. In Japanese culture, the concept of just doing what you want without at least making a show of gathering some sort of consensus is viewed in a much more negative light – it’s selfish, arrogant, and often leads to bad results.
Writing senkou as 先行 (“going first,” “seizing priority”) may feel thematically apt, but is considered an error.