mittelhochdeutsch, althochdeutsch sin(t)vluot, unter Einfluss von ↑Sünde zu mittelhochdeutsch sin(e)-, althochdeutsch sin(a)- = immerwährend; gewaltig und ↑Flut It looks like "Sint" has its roots in Old and Middle High German, meaning "huge, major". Sintflut is typically used to refer to the biblical flood, but exists also in colloquial figures of speech, such as: "Nach mir die Sintflut" (I don't care what happens after I'm gone) "Es ist die reinste Sintflut" (Everything's completely flooded)