An Etymological Dictionary of the German Language/Annotated/streben
streben, verb, ‘to strive, struggle, endeavour,’ from Middle High German strëben, weak verb, ‘to move violently, exert oneself, contend.’ The Old High German strong verb corresponding to the non-recorded weak verb *strëbên would be *strîban (*strîfan?), as is assumed by the Romance loan-words. Compare Old French estriver, ‘to fight, wrestle,’ estrif, ‘contest,’ whence English to strive, strife, are borrowed.