Pues sí es un término negativo, quiere decir que te vales de malas maneras(mañas) para realizar/conseguir algo. (it means you cheated, not in sentimental ways, in this case could be that you cheated on the test and that stuff) Pero depende mucho de la situación, la persona que te lo dijo y el tono con el que lo dijo, podría haber estado bromeando (like when you say "i hate you" to your close friend,most of the cases you don't really mean it)

Yes. It's not something nice to say to someone. Tramposa means that you are a cheater. You cheated to do something.

Tramposa is cheater

Why?

hola