Unsay comes from un- ('reversal') + say, from Old English secgan ('to say, speak'), from Proto-Germanic *sagjaną. In current use it is a verb meaning "to retract or take back something said". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The prefix un- is reversative here, marking an undoing or release rather than mere negation. The surface form is compositional: its joined elements remain visible in the modern word. The historical chain includes Old English un-, Old English secgan, and Proto-Germanic *sagjaną. Related English forms include say, said, and gainsay. Derived forms include unsaid and unsaying. As a result, the modern word is best read as a negative, privative, or reversative formation built on a historically older base.