Etymon
pie-ne-protoindoeuropean-n-protogermanic-un-protowest-germanic-un-old-english-un-middle-english-un-english-un-protogermanic-skamo-protowest-germanic-skamu-old-english-scamu-protoindoeuropean-pleh1-protoindoeuropean-nos-protoindoeuropean-plh1nos-protogermanic-fullaz-protogermanic-fullaz-old-english-ful-old-english-sceomfull-middle-english-schameful-english-shameful-english-unshameful-from-un-shameful
A dedicated page for this root is on the way — it will gather every word descended from it, sibling forms across daughter languages, and a branching map of the family tree.