Etymon
gem-arijaz-protowest-germanic-ari-old-english-ere-middle-english-ere-english-er-english-fucker-english-motherfucker-compound-of-mother-fucker-attested-since-1918
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.