[a. Fr. alerte, formerly allerte, à l’airte, 16th c. ad. It. milit. phr. all’ erta on the watch, on the look-out = alla to the, at the, erta a look-out, ‘a high watch tower’ (Florio), literally something erected or raised aloft, fem. of erto, pa. pple. of ergere:—L. ērigĕre to ERECT. From being used as an adv. phr., stare all’ erta, se tenir à l’ erte ‘to stand on the watch,’ it became a predicative and complemental, and at length an attributive adj. and a sb. When alert was established as a real adj. in Eng., the adv. phr. became ‘on the alert,’ etymologically pleonastic = on the à l’erte. Cf. the similar histories of alarm, alamort, alamode, in which adv. phrases have become more or less adj. or sb.]
A. adv. On the watch, on the look-out: hence adj. (in the compl. or pred.) Watchful, vigilant, wide-awake. a. as a military term.
1598. Barret, Theor. Warres, Gloss. 249. Alerta, an Italian word, vsed vnto the souldiers, when there is any suspition of the enemy, and signifieth to be watchfull, carefull, and ready.
1618. R. Williams, Act. Low Countr., 27 (T.). The prince finding his rutters alert (as the Italians say).
1707. Freind, Peterboro’s Cond. Spain, 213. Dear Jones, prove a true Dragoon, be diligent and alert.
1780. Ann. Reg., 64/1. Their situations were often so alert that no persons slept out of their clothes.
1879. Froude, Cæsar, xxiv. 417. The Pompeys were alert on the water to seize stray transports or provision ships.
b. generally.
1735. Geo. Ld. Lyttelton, Pers. Lett. (1776), I. 186. The people were kept Alert and upon their guard.
1799. S. Turner, Anglo-Sax. (1828), I. vii. 169. Caledonian wanderers would be alert to profit by the opportunity.
1866. Macgregor, 1000 M. in Rob Roy, i. 1. An interest ever varied with excitement keeps fully alert the energies of the mind.
1880. Cyples, Hum. Exp., vi. 152. Every sense is stirring; he is wholly alert.
B. adj. Quick in attention and motion, lively, brisk, active, nimble.
1712. Addison, Spect., No. 403, ¶ 5. I saw an alerte young Fellow that cocked his Hat upon a Friend of his.
1818. Scott, Rob Roy, 115. He is an alert, joyous, and lively old soul.
1859. Thoreau, Lett. (1865), 180. You can … carry any fortress with an army of alert thoughts.
Compared -er, -est, or more, most.
1754. Richardson, Grandison (1766), V. 73. Miss Byron … is one of the alertest in [these amusements].
1767. Burke, Corr. (1844), I. 134. I never knew him talk in a more alert, firm, and decided tone.
1793. Smeaton, Edystone L., § 298. One of the most alert of the masons.
1843. Carlyle, Past & Pr. (1858), 272. None of the alertest.
C. sb. [mod. Fr. alerte, subst. use of the original phrase, used as a military call. Cf. alarm.
1. The call to ‘look out’ for an attack; an alarm; hence, that which amounts to such a call, a ‘waking up,’ a sudden attack or surprise.
1803. Wellington, in Gurwood, Desp., II. 286. I am glad to find that you have given the Enemy an Alert.
1826. Scott, Woodst., vii. (1846), 79. No man ever saw me drink when an alert was expected.
1870. Ev. Standard, 17 Sept. In case of an alert, every battalion, every company, and every man know their stations.
2. On the alert: on the look-out, on the watch. (Takes the place of the earlier alert adv. = all’ erta.)
1796. Campaigns 1793–4, II. vi. 31. The troops were … kept constantly on the Alerte.
1827. Hare, Guess. Truth, Ser. I. (1873), 181. Open evil at all events does this good: it keeps good on the alert.
1835. Marryat, Jac. Faithf., xxxviii. 132. But those who were stationed at the look-out were equally on the alert.
1882. 19th Cent., No. 69, 736. The men are for ever on the alert to find out something wrong.
