care·ful / ˈke(ə)rfəl/ • adj. 1. making sure of avoiding potential danger, mishap, or harm; cautious: I begged him to be more careful. ∎ (careful of/about) anxious to protect (something) from harm or loss; solicitous: he was very careful of his reputation. ∎ prudent in the use of something, esp. money: Ali had always been careful with money.2. done with or showing thought and attention: a careful consideration of the facts.DERIVATIVES: care·ful·ly adv.care·ful·ness n.