From Colawikki
Finesse determines the probability that a melee attack on a player will fail.
When an attacking player makes a melee attack (by holding down the left mouse button and pressing one of the cursor keys) the attacker's CCS meter decides a target based on the locations of nearby players. When the melee attack reaches the selected target's meter, it will make a calculation of the probability that the target escaped the attack; the maximum probability of 0.33 is reached when finesse is 100.
Please note that this is not to be confused with hit chance. The hit chance is a property of the attacking player, and may result in no attack being made even though a suitable player is in range. Finesse is a property of the attacked player and only comes into consideration if the attack *is* detected.
