What is a good finesse weapon?

I don't know if you want it to be graphically specific but generally weapons like the fan, whips, 8 and 9 section chain whips, Chinese straight sword [what people call a tai chi sword] and naginata are weapons that require finesse over brute strength.

These are just a few as you could add daggers, kobutons [excuse spelling], darts and other such things to the very long list.

Fan: sneaky, diversion weapon, loud, can be used as a short stick when folded

Whips: A lot of technique to use but they can be moved at over 80 mph- by females- and can do a lot of damage in the right hands

Straight sword: requires a skilled practitioner. Double edged weapon, cannot rely on heavy blocks or attacks. Good for taking out organs, soft targets and tendons. Relies on evasion/attack rather than battering attacks.

Naginata: If 4 foot Japanese samurai women can wield them to the point of beating up their male counterparts.... it speaks for itself I reckon.

It depends on the setting. In Europe the small sword is a very light and agile weapon. In China the gim is the light sword of choice (think crouching tiger hidden dragon) Both of these swords are regular length, but the blade is very thin to make it light. These swords are usually more for thrusting than cutting though. Or if you want a cutting weapon you can get shorter swords, and there are plenty of these in the world. These are usually considered as long knives though. Most other weapons tends to require more power. I think bo staffs are pretty light and fast, and you also have bows and guns. But not long bows as those requires a lot of power to use.

James G gave you some good suggestions. But a few more are.

The wind and fire wheels, a very elegant weapon. Good for close range. Perhaps your character use these in addition to a main weapon. http://upload.wikimedia.org/wikipedia/commons/thum...

The Jian. The poster child for sleek weapons. A resonating ringing sound is sometimes heard when you slice certain materials. http://i00.i.aliimg.com/wsphoto/v0/659223232/Young...

Shuko. An old Japanese tool, used for climbing, but since its fiction, you can use it as a weapon. It goes on the hands. http://www.kaswords.com/ProductImages/ninja_gear/n...

Twin hook swords. A good choice either way. https://www.mainemilitary.com/productcart/pc/catal...

The majority of weapons favor finesse. But those are a few to to play around with.

I really like kitanas because its is designed for speed, strength, and agility :) it is one of the most deadliest swords and it is a near perfection martial arts weapon :D

A gun. U dont need any strength.