suzerain n.

early 14c., of persons, "great, superior, supreme;" mid-14c., "having supreme power;" from Old French soverain "highest, supreme, chief," from Vulgar Latin *superanus "chief, principal" (source also of Spanish soberano, Italian soprano), from Latin super "over" (from PIE root *uper "over"). Of remedies or medicines, "potent in a high degree," from late 14c.

late 14c., "to raze, destroy, overthrow, undermine, overturn," from Old French subvertir "overthrow, destroy" (13c.), or directly from Latin subvertere "to turn upside down, overturn, overthrow," from sub "under" (see sub-) + vertere "to turn, turn back, be turned; convert, transform, translate; be changed" (from PIE root *wer- (2) "to turn, bend"). Related: Subverted; subverting.

late 15c., suserente, "supremacy," from Old French suserenete "office or jurisdiction of a suzerain" (Modern French suzeraineté), from suserain (see suzerain). Modern use (by 1823) probably is a re-borrowing and for 20 years or so it was treated as a French word in English.