class act

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One of distinctive and superior quality.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An entity exhibiting high class especially through refinement of demeanor, conscientiousness of behavior, and/or skillfulness in performance; or an exhibition of high class especially of one or more of those types:
• noun Used sarcastically, a person, entity, event, or action entity exhibiting the opposite of the above characteristics, i.e., boorish, unprincipled, and/or bungling behavior

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun someone who shows impressive and stylish excellence