speculation
🇺🇸
/ˌspekjuˈleɪʃn/
🇬🇧
/ˌspekjuˈleɪʃn/
guessing about something without knowing all the facts
There was much speculation about why he left his job suddenly.
buying and selling things hoping to make money, but risking loss
Stock market speculation can lead to big gains or big losses.