Openness to experience is a capacity within oneself to apprehend, absorb, and appreciate the world in its multitude of aspects and dimension. Within a set of available senses, it is one’s ability to distinguish nuance, shades of grey, meaning and detail in a given environment or situation. Blocks to openness could range from emotionally limiting frames of reference, prejudice or pre-conception, and self-concept to physical or mental health limitations.
See Myers-Briggs type indicator; http://en.wikipedia.org/wiki/Myers-briggs Introvert v. Extrovert and Judging v. Perceiving.
Also see Japanese terms: Hoshin; peace of mind, and Zanshin; martial awareness. http://en.wikipedia.org/wiki/Zanshin
Also see: honesty, directness, frankness, sincerity, candidness, ingenuous, receptivity, accessibility, interest, approachability, user friendliness, authenticity, genuineness, and spontaneity.