Here is a list of characteristics that are common to gifted adults, sans the references. You can read the rest of the article here.
A broad knowledge base and seemingly insatiable need for new information that is associated with an insatiable intellectual curiosity. Critical self-scrutiny and self-monitoring. Verbal agility, remarkable expressiveness, and a penchant for in-depth discussion and debate. Exceptionally high standards, idealism, perfectionism, and intense self-criticism. Preference for complexity and novelty and a tolerance of ambiguity. Excitability, multiple interests, high levels of energy... Love of challenge motivated by an intrinsic drive toward fulfillment of potential, meaningful living, and self-actualization. Distinct need for autonomy. Heightened physiological sensitivity and sensory arousal. Feelings of loneliness and emotional distance despite positive relationships and even popularity. Emotional sensitivity and extraordinary responsiveness. History of frustration related to asynchronous development — ability to visualize or conceptualize the desired creative product preceding the attainment of obligatory skills. Compassion, moral integrity and courage, wisdom, global awareness, and potential for humanitarian leadership.