Finger tight is a relative term and doesn't have a definitive answer. In general, finger tight means that you should be able to tighten the screw or nut by hand, without the need for tools.
How much torque you can apply with your fingers depends on a number of factors, including the size of the screw or nut, the material it's made from, and how strong your fingers are. As a rough guide, most people can generate between 30 and 50 inch-pounds (in-lbs) of torque with their fingers.
Of course, there will always be outliers at either end of the spectrum. Some people may be able to generate more than 50 in-lbs of torque with their fingers, while others may struggle to get past 30 in-lbs.