The "big five" personality traits are specifically termed extraversion, agreeableness, openness to experience, conscientiousness and neuroticism. Some psychologists say these broad, yet independent, attributes of human character describe and determine our overall personality.
Each of the five aspects can be described as a subset of specific idiosyncrasies. Openness includes a prevailing desire for variety, and an appreciation of creativity. A person measuring high in openness is more likely to think in abstractions, and have unconventional beliefs. Low openness scorers are traditional folks, generally uncomfortable with ambiguity.
Conscientiousness is a natural propensity for discipline and achievement and an instinct for planning. Someone who rarely controls her impulses may score low in conscientiousness.
Extraversion is a trait pertaining to an individual's desire to socialize, and to what extent she becomes energized by the attention she receives from other people. Low-scoring people are not necessarily unfriendly, but would never deliberately be the center of attention.
Agreeableness involves one's level of empathy and kindness. Individuals exhibiting agreeableness are often more trusting, helpful people. One who routinely suspects people's motives is not likely to score well in agreeableness.
To avoid offending people, the phrase "need for stability" is often used as another name for the trait neuroticism, especially in the business world. Someone measuring low in neuroticism experiences less anger, fear and sadness. A high level indicates a less emotionally stable individual, prone to persistent negative thoughts.
The theory of the five traits is also termed Five Factor Model, or FFM. Although FFM has received criticism, the theory is a widely analyzed one, and the five basic characteristics are known to have been arrived at independently (with slightly different wording) by at least four different researchers.