Tact, address, poise, savoir faire can all mean the skill and grace with which a well-bred person conducts himself in his relations with others.
Tact stresses skill and considerateness in one’s association with or handling of others, whether social equals or not. It implies delicate and sympathetic perception, especially of what is fit, graceful, or considerate under given circumstances.
Address stresses dexterity and grace in approach (as in meeting strangers or in coping with new or with difficult situations). It often connotes adroitness and suavity and commonly implies success in winning favor or in attaining one’s ends.
Poise often implies both tact and address; it stresses, however, self-possession or equanimity in meeting embarrassing or upsetting situations.
Savoir faire may stress worldly or social experience and a knowledge of what is the proper thing to say or do or of how to act under all circumstances. But it as often suggests a seemingly intuitive ability to act appropriately and with the utmost ease and tact rather than one based on breadth of experience.