buggery n.

"sodomite," 1550s, earlier "heretic" (mid-14c.), from Medieval Latin Bulgarus "a Bulgarian" (see Bulgaria), so called from bigoted notions of the sex lives of Eastern Orthodox Christians or of the sect of heretics that was prominent there 11c. Compare Old French bougre "Bulgarian," also "heretic; sodomite."

The softened secondary sense of "fellow, chap," is in British English "low language" [OED] from mid-19c. The meaning "something unpleasant, a nuisance" is from 1936. Related: Buggerly.

The religious heretics in question were the Bogomils, whose name is a Slavic compound meaning "dear to God" (compare Russian bog "god") and might be a translation of Greek theophilos.

suffix indicating state, condition, or quality; also activity or the result of it (as in victory, history, etc.), via Anglo-French and Old French -é, from Latin -ia, Greek -ia, from PIE *-a-, suffix forming abstract or collective nouns. It is etymologically identical with -ia and the second element in -cy, -ery, -logy, etc.