Question: In karaniya metta sutta,

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> He who is skilled in (working out his own) well being, and who wishes to attain that state of Calm (Nibbana) should act thus: he should be dexterous, **upright**, **exceedingly upright**, obedient, gentle, and humble.
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What does it mean to be upright?

Answer: 
> 
> What does it mean to be upright?
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It means to go to great lenghts to follow Buddhist ethics as taught by the Buddha - at least keeping the 5 precepts if being a layperson.
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> araṇīyam'atthakusalena
> Yaŋ taŋ santaŋ padaŋ abhisamecca:
> ***Sakko** ujū* ca *sūjū* ca,
> Suvaco cassa mudu anatimānī.
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Practicing "respectfully, carefully, duly, thoroughly", very, very... more in [Karaṇīya Metta-Sutta](https://zugangzureinsicht.org/html/lib/authors/nanadassana/metta_en.html#cult)

(Upright is something only reached by stream enter, while metta to practice is open for worldlings as well.)