dint: [OE] Dint originally signified a ‘blow’ or ‘hit’, particularly one inflicted by a sword or similar weapon. Its meaning broadened out in the 14th century to ‘force of attack or impact’, and this is the source of the modern English phrase by dint of, which to begin with denoted ‘by force of’. In the 13th century a variant form dent arose, which by the 16th century had moved on metaphorically to the sense ‘depression made by a blow’.
Old English dynt "blow dealt in fighting" (especially by a sword), from Proto-Germanic *duntiz (cognates: Old Norse dyntr "blow, kick"). Phrase by dint of ... "by force of, by means of," is early 14c.