VVS is simply the abbreviation for "very very slight" inclusions. Diamonds that are graded VVS contain imperfections that are considered minute and are extremely difficult (VVS1) or very difficult (VVS2) for a skilled grader to locate under 10x magnification.
In VVS1, they are extremely difficult to see, visible only from the pavilion, or small and shallow enough to be removed by a minor repolishing. In VVS2, they are still very difficult.
To check these out under the scope is quite awesome as the inclusions are usually nothing more than a speck or pinpoint. As you'll see, it's very important to examine diamonds clean as the smallest amount of dust could be mistaken for an imperfection. Most diamonds in jewelry stores that have been sitting in showcases have most assuredly collected some dust, if there are any VVS clarity diamonds in stock.
Very, Very Slightly Included category (VVS) diamonds have minute inclusions that are difficult for a skilled grader to see under 10x magnification. The VVS category is divided into two grades; VVS1 denotes a higher clarity grade than VVS2. Pinpoints and needles set the grade at VVS