Many seem to agree with the government that we should just let bygones by bygones.
But Lieberman's call to let bygones be bygones rings as hollow as his promise to draw troops down from Iraq.
"things that are past," especially offenses, 1560s, from plural of noun use of bygone (q.v.).
early 15c., from by (adv.) + gone. Cf. similar construction of aforesaid. As a noun from 1560s (see bygones).