speculation vs hypothesis

speculation and hypothesis both are nouns.

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

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

speculation: a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)
hypothesis: a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena

Other hypernyms of speculation include possibility, theory.

As nouns, speculation and hypothesis are synonyms defined as:

speculation and hypothesis: a message expressing an opinion based on incomplete evidence

Other synonyms of speculation include conjecture, guess, supposition, surmisal, surmise.

speculation (noun)	hypothesis (noun)
a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)	a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
continuous and profound contemplation or musing on a subject or series of subjects of a deep or abstruse nature	a proposal intended to explain certain facts or observations
a message expressing an opinion based on incomplete evidence	a message expressing an opinion based on incomplete evidence
an investment that is very risky but could yield great profits