If you are circumspect, you think carefully before doing or saying anything. A good quality in someone entrusted with responsibility, though sometimes boring in a friend.
The word circumspect was borrowed from Latin circumspectus, from circumspicere "to be cautious." The basic meaning of Latin circumspicere is "to look around." Near synonyms are prudent and cautious, though circumspect implies a careful consideration of all circumstances and a desire to avoid mistakes and bad consequences.