An 'opinion' is a belief you choose to hold — Latin distinguished it from knowledge since antiquity.
A view or judgment formed about something, not necessarily based on fact or knowledge.
From Old French opinion, from Latin opīniō (opinion, conjecture, belief, reputation), from opīnārī (to think, to believe, to suppose, to conjecture), probably connected to optāre (to choose, to wish for), from PIE *op- (to choose, to select, to prefer). An opinion is etymologically something chosen — a belief selected rather than a fact received. The same PIE root *op- underlies Latin optio (choice, the right to choose), optimus (best, most chosen), and English
In Roman philosophy, 'opīniō' was specifically contrasted with 'scientia' (knowledge). An opinion was an uncertain belief, possibly wrong, while knowledge was certain and demonstrated. Plato made the same distinction in Greek between 'doxa' (opinion, belief) and 'epistēmē' (knowledge). This