'ologist

A variety of 'ologists insist that the physiological and psychological changes of adolescence impose severe strains on the whole personality.

I suppose there are no end of 'ologists who will frown at my penchant for firearms and swear that it makes me a mother-fixated, bed-wetting psycho with a small penis.

After thanking her for her interest in the series and the kind words, I responded, “I hate to disappoint you, but I am not an 'ologist.'”