to obtain: to come to have something one has sought or been granted
In this use the word describes reaching or coming into possession of something, and it usually points to the thing gained: peace, help, a resurrection, a ministry, care in one's need. English "obtain" or "attain" fits it well.
One shade is easy to miss. The word often frames the outcome as something that falls to a person or is granted to them, not only something they went out and secured by their own effort. Paul says he stood firm because he "obtained help from God" (Acts 26:22), and the faithful of old endured torture in hope of "a better resurrection" (Hebrews 11:35). The attaining is real, but it comes as much as it is won.
This is close to the ordinary verb for taking or receiving (λαμβάνω), and closer still to its own strengthened relative (ἐπιτυγχάνω), which narrows in on succeeding at getting a specific thing.