television vs idiot box

television and idiot box both are nouns.

Word	Noun	Adjective	Verb	Adverb
television	Yes	No	No	No
idiot box	Yes	No	No	No

As nouns, television and idiot box are synonyms defined as:

television and idiot box: an electronic device that receives television signals and displays them on a screen

Other synonyms of television include boob tube, goggle box, television receiver, television set, telly, tv, tv set.

television (noun)	idiot box (noun)
a telecommunication system that transmits images of objects (stationary or moving) between distant points	an electronic device that receives television signals and displays them on a screen
an electronic device that receives television signals and displays them on a screen
broadcasting visual images of stationary or moving objects