An informal party is a gathering of people for socializing and entertainment. It can be referred to as a SOCIAL (6 letters), MIXER (5 letters), SMOKER (6 letters), or openhouse (9 letters). A SOCIAL is a gathering of people for the purpose of conversation and companionship. A MIXER is an event where people can meet and mingle with each other. A SMOKER is a type of informal party where smoking is allowed. An openhouse is an informal party where guests are invited to come and go as they please.