acting out vs outburst

acting out and outburst both are nouns.

Word	Noun	Adjective	Verb	Adverb
acting out	Yes	No	No	No
outburst	Yes	No	No	No

As nouns, outburst is a hypernym of acting out; that is, outburst is a word with a broader meaning than acting out:

acting out: a (usually irritating) impulsive and uncontrollable outburst by a problem child or a neurotic adult
outburst: an unrestrained expression of emotion

Other hypernyms of acting out include blowup, ebullition, effusion, gush.

acting out (noun)	outburst (noun)
a (usually irritating) impulsive and uncontrollable outburst by a problem child or a neurotic adult	a sudden violent disturbance
(psychiatry) the display of previously inhibited emotions (often in actions rather than words); considered to be healthy and therapeutic	an unrestrained expression of emotion
	a sudden intense happening