What is the meaning of Smart_money?

Experienced, well-informed investors, gamblers, etc. considered as a group.

The money invested or bet by such people; by extension, the opinions of such people.

Money paid by a person to buy himself off from some unpleasant engagement or some painful situation.

Money allowed to soldiers or sailors, in the English service, for wounds and injuries received; also, a sum paid by a recruit, previous to being sworn in, to procure his release from service.

Vindictive or exemplary damages; damages beyond a full compensation for the actual injury done.

Source: wiktionary.org