"personality" can be defined as how a person acts,talks, likes, dislikes, favours, and ect

the biggest software of our hardware(brain) , yet subject to many viruses..

I don't agree about defining personality, I think this word cannot be defined 'cause people have not a lot in common to define it, if you told me how to define space-time then I'd tell you some physics theories in relativity 'cuz now we have a general view of it but I cannot tell you 'bout human things 'cuz they differ between humans

Personality & character are intertwined & often influenced by a person's environment as they grow up.

The totality of somebody's attitude, interests, behavioral patterns, emotional responses, social roles and other individual traits that endure over long periods of time.