the way of the world in our time; the frame of mind of people nowadays
A somewhat literary or old-fashioned term describing the prevailing attitudes, customs, or spirit of the present age. Often used in commentary on society or culture.
A novel reflecting the spirit of the times became a topic of conversation.
His way of thinking is exactly the frame of mind of people nowadays.
時代精神 is a more formal, philosophical term for 'Zeitgeist', while 当世気質 is a more literary, slightly old-fashioned expression focusing on the common people's attitudes.
世相 refers to the social conditions or phases of the world, often used in news or analysis, whereas 当世気質 emphasizes the temperament or disposition of people in the current era.
Compound of 当世 (tōsei, 'the present age') and 気質 (katagi, 'temperament, disposition'). The exact historical derivation is uncertain, but the term has been used since the Edo period to describe the prevailing spirit of the times.