also long-run, "ultimate outcome," 1620s, from long (adj.) + run (n.); the notion is "when events have run their course," as in the phrase in the long run "after a long course of experience." As an adjective from 1804.

"quarrel, confrontation," 1905, from the verbal phrase; see run (v.) + in (adv.). From 1857 as "an act of running in," along with the verbal phrase run in "pay a short, passing visit." Earlier to run in meant "to rush in" in attacking (1815).

"length of time taken in a particular task," 1974, originally in computing; see run (v.) + time (n.). In computing, run (n.) "instance of execution of a program" is by 1946.

"tending toward impropriety," 1867, from French risqué, past participle of risquer "to risk" (see risk (v.)).

late 13c., "without risk; without harm;" mid-14c., "without risk of error," from safe (adj.) + -ly (2).

also bio-hazard, "organic material that carries a significant health risk," 1973, from bio- + hazard (n.).

"danger, risk, hazard, jeopardy, exposure of person or property to injury, loss, or destruction," c. 1200, from Old French peril "danger, risk" (10c.), from Latin periculum "an attempt, trial, experiment; risk, danger," with instrumentive suffix -culum and first element from PIE *peri-tlo-, suffixed form of root *per- (3) "to try, risk."

"attended with risk, dangerous," 1825, from risk (n.) + -y (2). Riskful in same sense is from 1793. Related: Riskiness.  Riskless is attested by 1818.

1570s, "godless person, one who denies the existence of a supreme, intelligent being to whom moral obligation is due," from French athéiste (16c.), from Greek atheos "without god, denying the gods; abandoned of the gods; godless, ungodly," from a- "without" (see a- (3)) + theos "a god" (from PIE root *dhes-, forming words for religious concepts).

The existence of a world without God seems to me less absurd than the presence of a God, existing in all his perfection, creating an imperfect man in order to make him run the risk of Hell. [Armand Salacrou, "Certitudes et incertitudes," 1943]

1590s, "involving risk or danger," from un- (1) "not" + safe (adj.).