Other forms: speculated, speculates, speculating
To speculate is to guess at what might be true without the evidence to settle it. Two people in a car park deciding why the boss looked upset.
The word carries a faint warning, which is why broadcasters say it would be wrong to speculate — the guessing is admitted rather than hidden. It takes about, or a whole clause: speculate about the cause, speculate that he had already left. A separate financial sense means to buy something risky hoping the price will rise, and the person doing it is a speculator. The nouns split neatly, since speculation covers both meanings and speculator only ever means money.
To speculate is to keep watch. Latin speculor meant to observe or to spy, from specula, a watchtower, so the speculator was a lookout long before he was a gambler.
Proto-Indo-European
*speḱ-
Latin
speculātus
English, today
speculate
Built from
Latin speculātus, perfect active participle of speculor (“to watch, observe, examine, spy”) (see -ate), from specula (“a watchtower”), ultimately from speciō (“to look at”).
Etymology from Wiktionary, CC BY-SA