The system divides the ten signs into two classes. "Masculine" here is the name of a group, not a statement about a person's sex: both men and women are born under it, and it indicates nothing whatsoever about sex.
The trait shared across the class is a direction outwards and forwards. Such a person tends to think in tasks and deadlines, to build a plan and to lead along it — themselves and other people. They feel better where there is a goal and where it is clear what counts as reaching it.
The reverse side is maximalism. The bar is set high, an intermediate result is written off as worthless, and the people nearby not infrequently end up as part of the plan rather than parties to a conversation about it.