propagate vs broadcast

propagate is not a noun while broadcast is a noun.

Word	Noun	Adjective	Verb	Adverb
propagate	No	No	Yes	No
broadcast	Yes	No	Yes	No

As verbs, propagate and broadcast are synonyms defined as:

propagate (noun)	broadcast (noun)
	message that is transmitted by radio or television
	a radio or television show

propagate (verb)	broadcast (verb)
multiply sexually or asexually	cause to become widely known
cause to propagate, as by grafting or layering	broadcast over the airwaves, as in radio or television
cause to become widely known	sow over a wide area, especially by hand
transmit
transmit or cause to broaden or spread
become distributed or widespread
travel through the air
transmit from one generation to the next