"characterized by great effort," mid-15c. (implied in strenuously), from Latin strenuus "active, brisk, quick, nimble, prompt, vigorous, keen." Probably cognate with Greek strēnes, strēnos "keen, strong," strenos "arrogance, eager desire," Old English stierne "hard, severe, keen" (see stern (adj.)). Mocked by Ben Jonson as a pedantic neologism in "Poetaster" (1601). Sense of "requiring much energy" is first recorded 1670s. Related: Strenuousness; strenuosity.
1620s, "characterized by slaughter, attended by much bloodshed;" also bloodthirsty, eager to shed blood, delighting in carnage," from French sanguinaire or directly from Latin sanguinarius "of or pertaining to blood," also, rarely, "blood-thirsty," from sanguis (genitive sanguinis) "blood," a word of unknown origin. Latin distinguished sanguis, the generic word, from cruor "blood from a wound" (related to English raw, from PIE root *kreue-). The classical sense of "pertaining to blood" is rare in English.
1915, proprietary name (Corning Glass Works, Corning, N.Y.) of a type of hard, heat-resistant glass, an arbitrary coinage, in which advertisement writers and eager etymologists see implications of Greek pyr "fire" and perhaps Latin rex "king;" but the prosaic inventors say it was based on pie (n.1), because pie dishes were among the first products made from it. The -r-, in that case, is purely euphonious.
late 14c., declamacioun, "composition written to be declaimed," from Latin declamationem (nominative declamatio) "exercise in oratorical delivery; declamation;" in a bad sense, "loud, eager talking," noun of action from past-participle stem of declamare "to practice public speaking, to bluster," from de-, here perhaps an intensive prefix (see de-) + clamare "to cry, shout" (from PIE root *kele- (2) "to shout"). Meaning "a public harangue or speech" is from 1520s; sense of "act of making rhetorical harangues in public" is from 1550s.
"loud, disorderly, confusing noise," 1560s, probably imitative. Klein and Century Dictionary compare Gaelic racaid "noise, disturbance," but OED says this "is no doubt from Eng."
Meaning "dishonest activity" (1785) is perhaps an extended sense, from the notion of "something going on" or "noise or disturbance made to distract a pick-pocket's victim." Or it might be from racquet, via the notion of "a game," or from or reinforced by rack-rent "extortionate rent." There also was a verb racket "carry on eager or energetic action" (1753), and the gangster sense might be via the notion of "exciting and unusual." Weakened sense of "way of life, one's line of business" is by 1891.
c. 1300, curraunt, "running, flowing, moving along" (a sense now archaic), from Old French corant "running, lively, eager, swift," present participle of corre "to run," from Latin currere "to run, move quickly" (of persons or things), from PIE root *kers- "to run." Related: Currentness.
Sense of "presently in effect" is from mid-15c. Meaning "prevalent, generally reported or known" is from 1560s; that of "established by common consent" is from 1590s; that of "now passing, present now, in progress" is from c. 1600. Of money, "passing from one person to another," late 15c. Current events is attested from 1795; current affairs by 1776.