*bhrug-

"to endure," Old English brucan "to use, enjoy the use of, possess; eat; cohabit with," from Proto-Germanic *brukjanan "to make use of, enjoy" (source also of Old Saxon brukan, Old Frisian bruka "to use, practice," Dutch gebruiken "to use," Old High German bruhhan, German brauchen "to use, need," Gothic brukjan), from PIE root *bhrug- "to enjoy." The sense of "use" as applied to food led to that of "be able to digest," and by 16c. to "endure, tolerate," always in a negative sense. The original meanings have become obsolete.

"dead, deceased, extinct," 1590s, from Old French defunct (14c., Modern French defunt) or directly from Latin defunctus "dead," literally "off-duty," past-participle adjective from defungi "to discharge, finish," from de- "off, completely" (see de-) + fungi "perform or discharge duty" (see function (n.)).