Etymology
Advertisement
lax (n.)
"salmon," from Old English leax (see lox). Cognate with Middle Dutch lacks, German Lachs, Danish laks, etc.; according to OED the English word was obsolete except in the north and Scotland from 17c., reintroduced in reference to Scottish or Norwegian salmon.
Related entries & more 
Advertisement
lax (n.)
1951 as an abbreviation of lacrosse.
Related entries & more 
lax (adj.)
c. 1400, "loose" (in reference to bowels), from Latin laxus "wide, spacious, roomy," figuratively "loose, free, wide" (also used of indulgent rule and low prices), from PIE *lag-so-, suffixed form of root *sleg- "be slack, be languid."

In English, of rules, discipline, etc., from mid-15c. Related: Laxly; laxness. A transposed Vulgar Latin form yielded Old French lasche, French lâche. The laxists, though they formed no avowed school, were nonetheless condemned by Innocent XI in 1679.
Related entries & more 
laxity (n.)

1520s, from French laxité, from Latin laxitatem (nominative laxitas) "width, spaciousness," from laxus "loose, lax" (see lax). An earlier noun was laxation (late 14c.). Laxness is from 1630s.

Related entries & more 
lackadaisical (adj.)
"sentimentally woebegone" [Century Dictionary], 1768, lack-adaysical (Sterne), from interjection lackadaisy "alas, alack" (1748), a ludicrous alteration of lack-a-day (1690s), an exclamation of sorrow or regret, from alack the day (1590s). Hence, "given to crying 'lack-a-day,' vapidly sentimental." Sense probably altered by influence of lax. Related: Lackadaisically.
Related entries & more 
Advertisement
laxative (adj.)
late 14c., "causing relaxation or looseness," from Old French laxatif (13c.), from Medieval Latin laxativus "loosening," from Latin laxat-, past participle stem of laxare "loosen," from laxus "loose, lax" (see lax). The noun meaning "a laxative medicine, a medicine that relieves constipation by relaxing the intestines" is from late 14c.
Related entries & more 
lessee (n.)
"one to whom a lease is given," late 15c., from Anglo-French lesee, Old French lessé, past participle of lesser "to let, to leave" (10c., Modern French laisser), from Latin laxare, from laxus "loose" (see lax).
Related entries & more 
languor (n.)
c. 1300, "disease, sickness; distress, mental suffering," from Old French langor "sickness; weakness" (12c., Modern French langueur), from Latin languorem (nominative languor) "faintness, feebleness, lassitude," from languere "be weak or faint" (see lax). Sense in English shifted to "faintness, weariness" (1650s) and "habitual want of energy" (1825).
Related entries & more 
leash (n.)
c. 1300, "thong for holding a dog or hound," from Old French lesse, laisse "hound's leash," ultimately from Latin laxus "loose" (see lax), perhaps via noun use of fem. form laxa. The notion seems to be of a string loosely held. Figurative sense attested from early 15c. The meaning "a set of three, three creatures of a kind" is from early 14c., originally in sporting language and especially of greyhounds, foxes, bucks, or hares.
Related entries & more 
laissez-faire 
also laissez faire, 1822, French, literally "let (people) do (as they think best)," from laissez, second person plural imperative of laisser "to let, to leave" (10c., from Latin laxare, from laxus "loose;" see lax) + faire "to do" (from Latin facere "to make, to do" (from PIE root *dhe- "to set, put"). From the phrase laissez faire et laissez passer, motto of certain 18c. French economists, chosen to express the ideal of government non-interference in business and industry. Compare laisser-faire "a letting alone," taken to mean "non-interference with individual freedom of action" as a policy in government and political economy.
Related entries & more