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οὖσα

Ὄττω τις ἔραται -> Whatever one loves best | Whom you desire most
Sappho

French (Bailly abrégé)

ης;
fém. de ὤν, part. prés. de εἰμί.

Russian (Dvoretsky)

οὖσα: f к ὤν (part. praes. к εἰμί).