speculate

Universal Words verb 1 ~ (about / on sth) to form an opinion about sth without knowing all the details or facts: [V] We all speculated about the reasons for her resignation. * They were all speculating as to the identity of the stranger. * [Vwh-] It is useless to speculate why he did it. * [Vthat] We can speculate that the stone circles were used in some sort of pagan ceremony. 2 [V] ~ (in / on sth) to buy goods, property, shares, etc., hoping to make a profit when you sell them, but with the risk of losing money: He likes to speculate on the stock market.