yeah, read it's discription:
http://bulbage.com/pics/fallout2/traits/fast_shot.jpg
If you don't want to click the link i'll quote the important part:
You don't have time to aim for a targeted attack, because you attack faster than normal people.
thats why unlike FO3 it's IMPORTANT to read what the various traits and perks do before picking them.
Trait's have a good side and a bad side.