conjecture
con-jec-ture
verb
Form an opinion or conclusion about something without complete information.
"She conjectured he was late."
noun
An opinion or conclusion formed on the basis of incomplete information.
"His theory was pure conjecture."
Thesaurus
Synonyms: speculation, guess, hypothesis, surmise, supposition, surmisal, hypothesise, theorise, speculate, hypothesize, suppose, hypothecate