Amateur- (noun) one who engages in a pursuit, study, science, or sport as a pastime rather than as a profession. It also means someone who practices something without mastery of its essential parts. A football player is an amateur if they are playing for fun and game, but not playing for a professional team where they are getting paid.
Expert: an expert is someone having or
displaying special skills or knowledge developed through training, study, or
experience.
Investigate: When you investigate something
you observe or study by close examination and systematic inquiry. A well run
investigation has a clear method for documentation of the findings.