Speculate

投機 /投机

tóujī

(to make a risky trade)

投機倒把 /投机倒把

tóujī dǎobǎ

(to make a risky trade)

推測 /推测

tuīcè

(to make an inference based on inconclusive evidence)

沉思

chénsī

((obsolete in English) to meditate)

猜測 /猜测

cāicè

(to make an inference based on inconclusive evidence)