Mars in Libra, the fair fight
Mars in Libra means you go after what you want through other people: by persuading, partnering and negotiating instead of charging ahead alone. You fight hardest over fairness, and you find it hardest to fight for yourself without first checking it's reasonable.
Mars is your drive and your temper, how you compete, how you chase what you desire, how you act under pressure. Libra is cardinal air, the sign of balance and relationship, so here the planet of conflict spends a lot of energy trying to avoid conflict.
Mars in detriment, in plain words
Traditional astrology says Mars is in detriment in Libra, the sign opposite Aries, which Mars rules. In Aries, Mars acts alone and at once. In Libra it pauses to consider how everyone else will feel. That's the whole meaning of detriment: the planet's natural style runs against the sign's. It doesn't make this Mars weak. It makes it diplomatic, and diplomacy is a form of force that wins a lot of battles quietly.
The advocate
You're brilliant at fighting on someone else's behalf. Give you a friend who's been treated badly by a landlord or a manager, and you'll write the email that gets results, so calm and exact that nobody can argue with it. You see both sides of a dispute before the people in it do, which makes you the natural mediator in every group chat.
You work best with a partner. Projects come alive when there's someone to bounce off, and exercise is easier when it's tennis, dancing or a running buddy instead of a solo gym session.
Desire is drawn to grace. You're attracted to people who are charming and well put together, who are good company in a room full of strangers. Crudeness turns you off faster than almost anything.
The delayed explosion
The honest tension is anger you postpone. Because you want to be fair, you hold back until you're sure you're justified, and by then you've swallowed it twenty times. Then the twenty-first, a forgotten text, someone using the last of the milk, sets off the whole stored load, and you look like the unreasonable one. People who know you learn that the calm surface isn't the same as being fine.
Decisions are the other cost. Weighing every option fairly means some choices never get made, and in a group you'll let a worse plan go ahead rather than be the one who overrules it.
Alongside the rest of your chart
With a Libra Sun too, the whole personality leans toward harmony, and you need practice saying a plain no. A fire Sun gives you more appetite for open conflict. If your Venus is also in Libra, see Venus in Libra: charm and drive pull in the same direction. The opposite placement, Mars in Aries, shows the same planet with no pause at all. The Mars sign guide shows how to find yours.
Questions
How does Mars in Libra show anger?
Late. You try to be reasonable for a long time, then it comes out all at once, over something that looks small to everyone else.
Is Mars in Libra weak?
No. Detriment means it works against Mars's natural directness, so it wins through persuasion and timing instead of force.
What is Mars in Libra attracted to?
Charm, good manners and a sense of style. You want someone who's easy to be around and fair in a disagreement.