Why was "tantrum" trending last week?
word-forming element meaning "above; highest; across; too much; above normal; outer," from Old English ofer (see over). Over and its Germanic relations were widely used as prefixes, and sometimes could be used with negative force, though this is rare in Modern English. Cf. Gothic ufarmunnon "to forget," ufar-swaran "to swear falsely;" Old English ofercræft "fraud."