Sounds correct Im wondering if it instead comes from latin infact in italan witch is the most similar language we have the same word grave (with a different pronunciation ) to mean something important (not grave something not that important ) but grave its also an old word meaning something heavy like in old physics experiments ... So maybe it became to be as something like it's not a weight that heavy for me to carry if u don't do this thing ... more tied to the metaforical uncomfortableness given by a heavy weight ... feel free to correct me I have never done latin at school ... ( fun fact Yes more Italian than u think has done at least 5 years of latin )