A gifted student is one with an exceptional native intelligence.
The generally accepted measure of giftedness is an IQ score above 130. This is roughly the top 2% to 3% of all individuals.
Not all gifted individuals will fit the criteria of having a uniformly high general IQ score. Some people may score highly on some portions of an intelligence test while scoring low on others. Sometimes there are problems with test giving or test taking, although most testing professionals work very hard to minimize the effects of these problems.