gamble vs speculation

gamble and speculation both are nouns.

Word	Noun	Adjective	Verb	Adverb
gamble	Yes	No	Yes	No
speculation	Yes	No	No	No

As nouns, speculation is a hypernym of gamble; that is, speculation is a word with a broader meaning than gamble:

Other hypernyms of gamble include venture.

gamble (noun)	speculation (noun)
a risky act or venture	a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)
money that is risked for possible monetary gain	continuous and profound contemplation or musing on a subject or series of subjects of a deep or abstruse nature
	a message expressing an opinion based on incomplete evidence
	an investment that is very risky but could yield great profits

gamble (verb)	speculation (verb)
play games for money
take a risk in the hope of a favorable outcome