花心 literally means 'center of a flower' (the floral core), but in everyday speech it's far more common as a noun or adjective describing someone who is unfaithful or fickle in romantic relationships—a 'player' or 'love rat.' It's a culturally loaded term: calling someone 花心 implies emotional inconsistency rather than just cheating. As a noun, 花心 can refer to a person who is romantically unreliable (e.g., 他是个花心). The word does not appear in the literal sense very often outside botany or poetry; learners should master the figurative use first.