Viveka
विवेक (viveka)
Discernment - the practiced ability to tell the lasting from the passing, the real from the merely loud.
Viveka is usually translated discrimination or discernment: the capacity to separate what is essential from what is not. Vedanta gives it a precise assignment - distinguishing the unchanging witness from everything that changes - but its everyday form is recognisable to anyone: knowing which of today's twenty urgencies is actually important.
Discernment differs from judgement. Judgement ranks things against a preference; viveka sorts them by nature. It is quieter, less entertained by its own conclusions.
It sharpens with use. Reading slowly builds it; so does the practice of pausing before consenting to an impulse and asking what, exactly, is asking. Shankara placed viveka first among the qualifications of a student - before renunciation, before even calm - because without it, effort pours into the wrong vessels.