serious relationship; dating with marriage in mind
Used especially in contexts like matchmaking and dating apps to describe a relationship where both parties are looking for a marriage partner, not casual dating.
At marriage agencies, many people are looking for a serious relationship with marriage in mind.
I'm in a serious relationship with him, so we also discuss our future together.
交際 is a general term for socializing or dating, while 真剣交際 specifically implies a serious, marriage-oriented relationship.
婚活 refers to the activity of actively seeking a marriage partner, whereas 真剣交際 describes the nature of the relationship itself.
Compound of 真剣 (serious, earnest) and 交際 (association, dating). The term likely emerged in the context of modern matchmaking services to distinguish marriage-minded dating from casual relationships.