When I go to some prom, wedding, do I have to go completely formal? The answer is no. There is a special style that stays "on the wall" when it comes to formality. The style known as "fine sport" is a more social, yet lightweight outfit. The idea is to dress well, with elegance, but without abusing the formality. Another name that this style receives is costume walk and is between the social attire and the casual chic.
But then, what can I use?