Definitions of caution:

• noun:   the trait of being cautious; being attentive to possible danger

  Example: "A man of caution"

• noun:   judiciousness in avoiding harm or danger

  Example: "He exercised caution in opening the door"

• noun:   a warning against certain acts
• noun:   the trait of being circumspect and prudent
• verb:   warn strongly; put on guard