activeness vs eruption

activeness and eruption both are nouns.

Word	Noun	Adjective	Verb	Adverb
activeness	Yes	No	No	No
eruption	Yes	No	No	No

As nouns, eruption is a hyponym of activeness; that is, eruption is a word with a more specific, narrower meaning than activeness:

Other hyponyms of activeness include agency, busyness, hum, behavior, behaviour, eructation, extravasation, operation, overdrive, play, swing.

activeness (noun)	eruption (noun)
the trait of being active; moving or acting rapidly and energetically	the sudden occurrence of a violent discharge of steam and volcanic material
the state of being active	a sudden very loud noise
	the emergence of a tooth as it breaks through the gum
	a sudden violent spontaneous occurrence (usually of some undesirable condition)
	(of volcanoes) pouring out fumes or lava (or a deposit so formed)
	symptom consisting of a breaking out and becoming visible