B2used to express that you are certain or almost certain about something: The fault surely lies in the design of the equipment.US"May I sit here?" "Surely." (= Yes, certainly.)Without more food and medical supplies, these people will surely not survive.Confidence and self-assuranceShowing arrogance and conceitB2used to express surprise that something has happened or is going to happen: Surely you don't expect me to believe that?Surely you're not going out on a night like this?Expressions of surprise