0 past simple and past participle of speculate
1 to guess possible answers to a question when you do not have enough information to be certain:
I don't know why she did it - I'm just speculating.
A spokesperson declined to speculate on the cause of the train crash.
Journalists are speculating about whether interest rates will be cut.
[ + that ] The newspapers have speculated that they will get married next year.
2 to buy and sell in the hope that the value of what you buy will increase and that it can then be sold at a higher price in order to make a profit:
It's useless to speculate without more information.
Royal-watchers have once again been speculating on the health of the princess.
Scientists have speculated about the possibility of parallel universes.
Many have speculated as to the mysterious nature of a wall that is soundproof in one direction and opaque in the other.
Many researchers have speculated as to why volunteering promotes positive outcomes.
The human mind is perfectly computable, maybe even classically, as we have speculated.
It could be speculated that this similarity is linked to the relatively low head position of stalking lions and of hyenas during scavenging on carrions.
I speculated that some or all of them might have been inserted by a copy editor.