early 14c., "confute or frustrate an opponent in argument, end an argument by winning it," from Latin concludere "to shut up, enclose," from assimilated form of com "together" (see con-) + -cludere, combining form of claudere "to shut" (see close (v.)).
Meanings "reach a mental determination, deduce; infer or determine by reason" are from late 14c., a sense also in Latin. General sense of "bring to an end, finish, terminate," and intransitive sense of "come to an end" are from late 14c. Meaning "settle, arrange, determine finally" is from early 15c. Sometimes in Middle English it was used in the etymological sense, "shut in" (late 14c.). Related: Concluded; concluding.
c. 1300, "despite, contempt," from Old French prejudice "a prejudice, prejudgment; damage" (13c.) and directly from Medieval Latin prejudicium "injustice," from Latin praeiudicium "prior judgment, judicial examination before trial; damage, harm," from prae- "before" (see pre-) + iudicium "judgment," from iudex (genitive iudicis) "a judge" (see judge (n.)).
Meaning "injury, physical harm" is mid-14c., as is the legal sense of "detriment or damage caused by the violation of a legal right." Meaning "preconceived opinion" (especially but not necessarily unfavorable) is from late 14c. in English; now usually "decision formed without due examination of the facts or arguments necessary to a just and impartial decision." To terminate with extreme prejudice "kill" is by 1972, said to be CIA jargon.
1570s, "to miscarry in giving birth," from Latin abortus, past participle of aboriri "to miscarry, be aborted, fail, disappear, pass away," a compound word used in Latin for deaths, miscarriages, sunsets, etc., which according to OED is from ab, here as "amiss" (see ab-), + stem of oriri "appear, be born, arise," from PIE *heri- "to rise" (see origin). [Watkins, contra de Vaan, etc., derives the second element from a suffixed form of PIE root *er- (1) "move, set in motion."]
The English word is attested from 1610s as "to deliberately terminate" anything (intransitive), but especially a pregnancy in a human or animal. Intransitive use in aeronautics and space-flight is by 1946. Transitive meaning "to cause (a woman) to miscarry" is recorded by 1916; with the fetus or pregnancy as the object of the action, by 1966. Related: Aborted; aborting. The Latin verb for "produce an abortion" was abigo, literally "to drive away."