lighten up vs irradiate

lighten up and irradiate both are verbs.

Word	Noun	Adjective	Verb	Adverb
lighten up	No	No	Yes	No
irradiate	No	No	Yes	No

As verbs, irradiate is a hyponym of lighten up; that is, irradiate is a word with a more specific, narrower meaning than lighten up:

Other hyponyms of lighten up include illume, illuminate, illumine, light, light up.

lighten up (verb)	irradiate (verb)
make more cheerful through the use of color	expose to radiation
become lighter	cast rays of light upon
become more cheerful	give spiritual insight to; in religion
make more cheerful