“Personality is that pattern of characteristic thoughts, feelings, and behaviours that distinguishes one person from another and that persists over time” “It is the sum of biologically based and learnt behaviour which forms the person's unique responses to
environmental stimuli” 

The Big Five personality traits, also known as the five factor model (FFM), is a model based on common language descriptors of personality (lexical hypothesis). These descriptors are grouped together using a statistical technique called factor analysis (i.e. this model is not based on scientific experiments). This widely examined theory suggests five broad dimensions used by some psychologists to describe the human personality and psyche. The five factors have been defined as openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism, often listed under the acronyms
“OCEAN”.