眉心成结
[méi xīn chéng jié]
'Frown formed knot between eyebrows'. An idiomatic expression referring to deep worry, perplexity, frustration showing on face when brows furrow. The knitted brow is a visual sign that the mind is tangled up inside, burdened by unresolved matters. It symbolizes the heavy-hearted nature of concerns not yet eased.