speculation

[1]	conjecture , guess , conjecture , guess , hypothesis , supposition , surmise , theory , guesswork , surmisal , hypothesis , postulation , surmise , supposition , opinion
[2]	thinking , conjecture , rumination , cogitation , reflection , meditation , contemplation , consideration , cerebration , pondering , wondering , deliberation , evaluation
[3]	gambling , venture , gamble , wagering , wager , taking (a) chance(s)/risk(s) , chance-taking
[4]	meditation