spark vs happen

spark is a noun but happen is not a noun.

Word	Noun	Adjective	Verb	Adverb
spark	Yes	No	Yes	No
happen	No	No	Yes	No

spark (noun)	happen (noun)
merriment expressed by a brightness or gleam or animation of countenance
a momentary flash of light
a small fragment of a burning substance thrown out by burning material or by friction
electrical conduction through a gas in an applied electric field
a small but noticeable trace of some quality that might become stronger

spark (verb)	happen (verb)
put in motion or move to act	come to pass
emit or produce sparks	come into being; become reality
	happen, occur, or be the case in the course of events or by chance
	come upon, as if by accident; meet with
	chance to be or do something, without intention or causation