worry vs onus

worry and onus both are nouns.

Word	Noun	Adjective	Verb	Adverb
worry	Yes	No	Yes	No
onus	Yes	No	No	No

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

Other hyponyms of worry include bugaboo, burden, encumbrance, incumbrance, load, business.

worry (noun)	onus (noun)
something or someone that causes anxiety; a source of unhappiness	an onerous or difficult concern
a strong feeling of anxiety

worry (verb)	onus (verb)
lacerate by biting
touch or rub constantly
be worried, concerned, anxious, troubled, or uneasy
disturb the peace of mind of; afflict with mental agitation or distress
be concerned with
be on the mind of