Definition: a person having very strong (potentially excessive) opinions and beliefs.
Common features:
(1) The person may want to convert others.
(2) The person may be willing to do things an average person would not do.
(3) The person may be viewed as radical.
Problems may arise if:
(1) a cult is the focus of the belief structure
(2) the person has a mental illness (obsessive, manic, psychopath, sociopath)
Negative aspects that may arise:
(1) intolerance of others, sometimes with a willingness to kill those who refuse to convert
(2) may be exploited by others (suicide bombers, etc)
