Shuō tā shì tiāncái yěxǔ yánguòqíshí, dàn tā quèshí cōngmíng.
Calling him a genius may be overstating it, but he's certainly smart.
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From 《三国志·蜀书·马良传》: Liu Bei on his deathbed warned Zhuge Liang that 'Ma Su's words go beyond his substance - he should not be given great responsibility.' Zhuge Liang ignored the advice, appointed Ma Su to defend Jieting (街亭), and the loss cost the Shu campaign.
usage
Neutral-to-negative. Describes claims, praise, reports, or ads that inflate reality. Common frames: 这么说有点言过其实 / 言过其实地夸奖. Compare with 夸大其词 (similar, slightly stronger) and 名不副实 (reputation doesn't match reality).
