When traveling through the city, tourists should be extra vigilant.
They were vigilant about protecting their children.
We remain vigilant against theft.
Over the years, as tension between pitchers and hit batsmen heightened to the point that hitters began rushing the mound, umpires have had to become far more vigilant about keeping the game from degenerating into a dogfight. —Buzz Bissinger, Sports Illustrated, 21 Mar. 2005
At the Château de Wideville's magnificent seventeenth-century gates, guests have their names ticked off by vigilant staff and then snake through a lugubrious park à l'anglaise. —Hamish Bowles, Vogue, September 2002
And as a foreign tourist in North Korea, under the care of vigilant minders who wanted me to see only the best, I had enjoyed the finest fare available. —Christopher Hitchens, Vanity Fair, January 2001
A vigilant hand had, as usual, kept the fire alive and the lamp trimmed; and the room, with its rows and rows of books, its bronze and steel statuettes of “The Fencers” on the mantelpiece and its many photographs of famous pictures, looked singularly home-like and welcoming. —Edith Wharton, The Age of Innocence, 1920
watchful, vigilant, wide-awake, alert mean being on the lookout especially for danger or opportunity. watchful is the least explicit term <the watchful eye of the department supervisor>. vigilant suggests intense, unremitting, wary watchfulness <eternally vigilant in the safeguarding of democracy>. wide-awake applies to watchfulness for opportunities and developments more often than dangers <wide-awake companies latched onto the new technology>. alert stresses readiness or promptness in meeting danger or in seizing opportunity <alert traders anticipated the stock market's slide>.