This root form (lemma) is used in 2 different forms in the NT: ἀποστασία (NFS), ἀποστασίαν (AFS).
It is glossed in 1 way: ‘apostasy’.
OET ACTS 21:21 Greek word=ἀποστασίαν (apostasian) Morphology=AFS English gloss=‘apostasy’ SR GNT ACTS 21:21 word 6
OET 2TH 2:3 Greek word=ἀποστασία (apostasia) Morphology=NFS English gloss=‘apostasy’ SR GNT 2TH 2:3 word 13