cautious

Synonyms: alert all ears cagey calculating chary circumspect considerate discreet forethoughtful gingerly hedging one’s bets heedful judicious keeping on one’s toes leery on the lookout playing it cool playing safe politic provident prudent pussyfoot safe shrewd taking it easy taking it slow tentative thinking twice vigilant walking on eggs wary watchful watching one’s step watching out with one’s eyes peeled

Antonyms: careless hasty heedless imprudent incautious rash thoughtless uncareful unguarded unobservant