1. formed a theory or conjecture about a subject without firm evidence
Usage: past tense of speculate
2. invested in stocks, property, or other ventures in the hope of gain but with the risk of loss
Usage: past tense of speculate; financial context

Examples

• Scientists speculated about the cause of the mysterious illness.
• She speculated that the meeting had been cancelled due to bad weather.
• Historians have long speculated about what really happened that night.
• He speculated in real estate during the housing boom.
• Many investors speculated on tech stocks in the 1990s.
• The newspaper speculated about the politician’s future plans.
• They speculated heavily in cryptocurrency and lost everything.