honorarium vs reward

honorarium and reward both are nouns.

Word	Noun	Adjective	Verb	Adverb
honorarium	Yes	No	No	No
reward	Yes	No	Yes	No

As nouns, reward is a hypernym of honorarium; that is, reward is a word with a broader meaning than honorarium:

honorarium (noun)	reward (noun)
a fee paid for a nominally free service	an act performed to strengthen approved behavior
	benefit resulting from some event or action
	the offer of money for helping to find a criminal or for returning lost property
	a recompense for worthy acts or retribution for wrongdoing
	payment made in return for a service rendered

honorarium (verb)	reward (verb)
	strengthen and support with rewards
	act or give recompense in recognition of someone's behavior or actions
	bestow honor or rewards upon