to refrain from noticing or recognizing: to ignore insulting remarks.
2.
Law.(of a grand jury) to reject (a bill of indictment), as on the grounds of insufficient evidence.
Origin: 1605–15; < Latinignōrāre to not know, disregard, verbal derivative of ignārus ignorant, unaware (with -ō- perhaps from ignōtus unknown), equivalent to in-in-3 + gnārus knowing, acquainted (with); akin to (g)nōscere to know1
1611, "not to know, to be ignorant of," from Fr. ignorer, from L. ignorare "not to know, disregard," from ignarus "not knowing, unaware" (see ignorant). Sense of "pay no attention to" first recorded 1801 and not common until c.1850.