CaesaryoudaoicibaDictYouDict
c. 1200, see caesarian; Old English had casere, which would have yielded modern *coser, but it was replaced in Middle English by keiser, from Norse or Low German, and later in Middle English by the French or Latin form of the name. Cæsar was used as a title of emperors down to Hadrian (138 C.E.), and also is the root of German Kaiser and Russian tsar (see czar). He competes as progenitor of words for "king" with Charlemagne (Latin Carolus), as in Lithuanian karalius, Polish krol. In U.S. slang c. 1900, a sheriff was Great Seizer.
competition (n.)youdaoicibaDictYouDict
c. 1600, "action of competing," from Latin competitionem (nominative competitio) "agreement, rivalry," noun of action from past participle stem of competere (see compete). Meaning "a contest for something" is from 1610s. Sense of "rivalry in the marketplace" attested from 1793; that of "entity or entities with which one competes" is from 1961, especially in business.
mad (adj.)youdaoicibaDictYouDict
late 13c., from Old English gemædde (plural) "out of one's mind" (usually implying also violent excitement), also "foolish, extremely stupid," earlier gemæded "rendered insane," past participle of a lost verb *gemædan "to make insane or foolish," from Proto-Germanic *ga-maid-jan, demonstrative form of *ga-maid-az "changed (for the worse), abnormal" (cognates: Old Saxon gimed "foolish," Old High German gimeit "foolish, vain, boastful," Gothic gamaiþs "crippled, wounded," Old Norse meiða "to hurt, maim"), from intensive prefix *ga- + PIE *moito-, past participle of root *mei- (1) "to change" (cognates: Latin mutare "to change," mutuus "done in exchange," migrare "to change one's place of residence;" see mutable).

Emerged in Middle English to replace the more usual Old English word, wod (see wood (adj.)). Sense of "beside oneself with excitement or enthusiasm" is from early 14c. Meaning "beside oneself with anger" is attested from early 14c., but deplored by Rev. John Witherspoon (1781) as an Americanism. It now competes in American English with angry for this sense. Of animals, "affected with rabies," from late 13c. Phrase mad as a March hare is attested from 1520s, via notion of breeding season; mad as a hatter is from 1829 as "demented," 1837 as "enraged," according to a modern theory supposedly from erratic behavior caused by prolonged exposure to poison mercuric nitrate, used in making felt hats. For mad as a wet hen see hen. Mad money is attested from 1922; mad scientist is from 1891.
Olympian (adj.)youdaoicibaDictYouDict
"of or belonging to Olympus," c. 1600; see Olympic + -ian. The noun meaning "a great god of ancient Greece" is attested from 1843, from Late Latin Olympianus, from Greek Olympios "pertaining to Olympus;" sense of "one who competes in the (modern) Olympic Games" is from 1976.
tragedy (n.)youdaoicibaDictYouDict
late 14c., "play or other serious literary work with an unhappy ending," from Old French tragedie (14c.), from Latin tragedia "a tragedy," from Greek tragodia "a dramatic poem or play in formal language and having an unhappy resolution," apparently literally "goat song," from tragos "goat" + oide "song" (see ode).

The connection may be via satyric drama, from which tragedy later developed, in which actors or singers were dressed in goatskins to represent satyrs. But many other theories have been made (including "singer who competes for a goat as a prize"), and even the "goat" connection is at times questioned. Meaning "any unhappy event, disaster" is from c. 1500.