‘莞尔而笑’ is a literary, elegant expression meaning ‘to smile gently’ or ‘to smile faintly and graciously.’ It conveys a soft, subtle, often warm or knowing smile — not loud or exaggerated, but quiet, composed, and sometimes slightly wry or affectionate. The phrase originates from classical Chinese and remains common in formal writing, literature, and refined speech.

Each character contributes to the nuance: 莞 (wǎn) originally meant ‘a type of rush plant,’ but here it’s used phonetically to evoke lightness; 尔 (ěr) is an archaic pronoun meaning ‘you’ or functions as a particle indicating manner; 而 (ér) is a conjunction linking actions smoothly (‘and then’ or ‘while’); and 笑 (xiào) means ‘to smile’ or ‘to laugh.’ Together, they form an adverbial phrase describing *how* one smiles — gently, fleetingly, with quiet charm.