speculate

verb

spec·​u·​late ˈspe-kyə-ˌlāt 

speculated; speculating

intransitive verb

1

a

: to meditate on or ponder a subject : reflect

b

: to review something idly or casually and often inconclusively

2

: to assume a business risk in hope of gain

especially : to make a relatively risky investment in something (such as stocks or real estate) in the hope of making a large short-term profit from market fluctuations

transitive verb

1

: to take to be true on the basis of insufficient evidence : theorize

2

: to be curious or doubtful about : wonder

speculates whether it will rain all vacation

Did you know?

It might be said that what separates our species from others is our tendency “to meditate on or ponder a subject.” That's the original 16th century meaning of speculate. It's a use not too distant from today's most common sense, which also involves the mind and thinking: when someone speculates about something, they think and make guesses about it, often forming ideas or theories when there are many things not known about the thing. But the origins of speculate lie not in thinking but in looking—the word comes from Latin specere, meaning “to look,” or “to look at.” We don't have to look far to find other specere descendants, and we'll point them out here with some italics: a cursory inspection reveals spectacle, spectrum, specimen, and perspective. Less conspicuous are despise, prospect, and species.

Synonyms

• guess
• assume
• suppose
• suspect
• think

Choose the Right Synonym for speculate

think, cogitate, reflect, reason, speculate, deliberate mean to use one's powers of conception, judgment, or inference.

think is general and may apply to any mental activity, but used alone often suggests attainment of clear ideas or conclusions.

teaches students how to think

cogitate implies deep or intent thinking.

cogitated on the mysteries of nature

reflect suggests unhurried consideration of something recalled to the mind.

reflecting on fifty years of married life

reason stresses consecutive logical thinking.

able to reason brilliantly in debate

speculate implies reasoning about things theoretical or problematic.

speculated on the fate of the lost explorers

deliberate suggests slow or careful reasoning before forming an opinion or reaching a conclusion or decision.

the jury deliberated for five hours

Examples of speculate in a Sentence

She could only speculate about her friend's motives.

He speculated as to whether she would come.

We don't know what happened—we can only speculate.

speculating on the stock market

Recent Examples on the Web

The researchers speculate that the behavior could be playful. —Melissa Hobson, Scientific American, 19 June 2025

The researchers also speculated that self-improvement could be a tool for enhancing AI safety. —Jeremy Kahn, Fortune, 19 June 2025

Federal prosecutors have declined to speculate about a motive. —Mark Vancleave, Los Angeles Times, 19 June 2025

When Netflix’s KPop Demon Hunters teaser trailer and images were first released, many K-pop fans began speculating who the K-pop idols in the film looked like. —Laura Sirikul, Forbes.com, 19 June 2025

Word History

Etymology

Latin speculatus, past participle of speculari to spy out, examine, from specula lookout post, from specere to look, look at — more at spy

First Known Use

1599, in the meaning defined at intransitive sense 1a

Rhymes for speculate

• abdicate
• abrogate
• acetate
• activate
• actuate
• adsorbate
• aggravate
• agitate
• alginate
• alienate
• allocate
• amputate

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Kids Definition

speculate

verb

spec·​u·​late ˈspek-yə-ˌlāt 

speculated; speculating

1

: to think or wonder about a subject

speculating about the future

2

: to engage in a business deal in which much profit may be made although at a big risk

speculator

-ˌlāt-ər 

noun

Legal Definition

speculate

verb

spec·​u·​late ˈspe-kyə-ˌlāt 

speculated; speculating

intransitive verb

1

: to theorize on the basis of insufficient evidence

Note: A jury is not permitted to speculate on a matter about which insufficient evidence has been presented in reaching its verdict.

2

: to assume a business risk in hope of gain

especially : to buy or sell in expectation of profiting from market fluctuations

transitive verb

: to take to be true on the basis of insufficient evidence

speculator

-ˌlā-tər 

noun