The word for today is…
speculate (verb) – 1. To engage in a course of reasoning often based on inconclusive evidence; conjecture or theorize.
2. To engage in the buying or selling of a commodity with an element of risk on the chance of profit.
Source : The Free Dictionary
Etymology : Speculate was adopted into English in the late 16th century from Latin speculatus, the past participle of the verb speculari, which means “to spy out” or “to examine.” Speculari, in turn, derives from specula, meaning “lookout post,” and ultimately from the Latin verb specere, meaning “to look (at).” Other conspicuous descendants of specere are inspect and suspect. Some less obvious descendants are the words despise, species, specimen, and as you may have speculated, conspicuous.