vice

Bad or immoral behaviour.

Pride is a vice, not a virtue.

Smoking was a vice Sally picked up in high school.

Any of various crimes related (depending on jurisdiction) to weapons, prostitution, pornography, gambling, alcohol, tobacco, or drugs.

Clipping of vice squad.

A defect in the temper or behaviour of a horse, such as to make the animal dangerous, to injure its health, or to diminish its usefulness.

So a horse with say, navicular disease, making him suitable only for light hacking, would probably be unsound, whereas rearing would be a vice, being a "defect in the temper... making it dangerous". A vice can however render a horse unsound - possibly a crib biter will damage its wind.

Alternative spelling of vise (“mechanical screw apparatus used for clamping”).

A tool for drawing lead into cames, or flat grooved rods, for casements.

A winding or spiral staircase.

A grip or grasp.

Fang. If I but fiſt him once: if he come but within my Vice.

Alternative spelling of vise (“to hold or squeeze with a vice”).

Camillo. As he had ſeen’t, or beene an Instrument / To vice you to't, that you haue toucht his Queene / Forbiddenly.

What could be done—who was it that could do it—to check the storm-flight of these maniacal horses? Could I not seize the reins from the slumbering coachman? […] [F]rom the way in which the coachman's hand was viced between his upper and lower thigh, this was impossible.