speculate
spec-u-late
verb
To form a theory or guess about something without firm evidence.
"People often speculate about the future."
verb
To invest in risky ventures hoping for quick, substantial profit.
"He decided to speculate on the stock market."
Thesaurus
Synonyms: hypothesise, theorise, hypothesize, suppose, conjecture, hypothecate, theorize, excogitate, ponder, meditate, mull over, contemplate