Definition of careful :
1. Filling with care or solicitude; exposing to concern, anxiety, or trouble; painful.
2. Full of care; anxious; solicitous.
3. Taking care; giving good heed; watchful; cautious; provident; not indifferent, heedless, or reckless; - often followed by of, for, or the infinitive; as, careful of money; careful to do right.
overcareful, noncommittal, metrical, troubled, apprehensive, on guard, wide-awake, sure, gingerly, ing how the land lies, minute, hard to please, elaborate, wakeful, close, frugal, calm, sparing, paying attention, farsighted, painstaking, narrow, self-disciplined, suspicious, calculating, sleepless, blow-by-blow, certain, economical, detailed, taking measures, thrifty, on the lookout, mensurable, putting the right foot forward, mensural, awake, canny, leery, metric, keeping a nose to the wind, exact, overexact, too-careful, self-possessed, studious, assiduous, calculated, forehanded, conservative, leaving no margin for error, going to great lengths, cool, measured, on the alert, religious, advertent, sure-footed, solid, making haste slowly, sober, chary, elaborated, unhurried, stealthy, protective
cautious (part of speech: adjective)
attentive (part of speech: adjective)
cautious, concentrating, observant, engrossed, diligent, entranced, alert, hearkening, heedful, regardful, watchful, immersed, considering, rapt, intent, enraptured, sharp, concerned, interested, observing, responsible, scrutinizing, vigilant, mindful, absorbed, fascinated, attentive
circumspect (part of speech: adjective)
fastidious (part of speech: adjective)
fussy, choosy, methodical, discriminating, Epicurean, qualmish, priggish, perspicacious, rigorous, accurate, squeamish, correct, discerning, punctilious, dainty, scrupulous, delicate, meticulous, proper, conscientious, mincing, critical, precise, exacting, severe, flawless, hypercritical, fastidious, prudish, finicky, picky, demanding, particular, prim, persnickety, literal
vigilant (part of speech: adjective)