An Etymological Dictionary of the German Language/freien
freien, vb., ‘to woo,’ from MidHG. vrîen, ‘to woo, marry’; unknown to UpG., prop. a LG. word, made current chiefly by Luther, Comp. Du. vrijen, ‘to sue for’ (MidHG. vrîen, ‘to set see, rescue,’ must in the main be regarded as a different word). In the sense of ‘to woo, marry,’ the verb must be directly connected with the OTeut. root frî, ‘to love’; comp. OSax. frî, ‘wife, beloved.’ For the diffusion of the Teut. root frî (from Aryan prî); see frei, Freitag, and also Freund.