An indefinite relative pronoun (genitive masculine singular form of ὅστις) meaning 'of whoever' or 'until which time.' It combines the relative ὅς with the indefinite τις to create a generalizing reference. In the NT it often carries temporal or conditional overtones: 'until it is accomplished' (Luke 12:50), 'until it bears fruit' (Luke 13:8), 'until it is fulfilled' (Luke 22:16). Matt 5:25 uses it in an urgent temporal clause ('while you are on the way'). The German 'solange' (as long as) and Spanish 'que' capture the durational-conditional sense that frequently attaches to this pronoun.