regression vs psychiatry

regression and psychiatry both are nouns.

Word	Noun	Adjective	Verb	Adverb
regression	Yes	No	No	No
psychiatry	Yes	No	No	No

regression (noun)	psychiatry (noun)
returning to a former state	the branch of medicine dealing with the diagnosis and treatment of mental disorders
the relation between selected values of x and observed values of y (from which the most probable value of y can be predicted for any value of x)
(psychiatry) a defense mechanism in which you flee from reality by assuming a more infantile state
an abnormal state in which development has stopped prematurely