Noun: individuals who decide to follow through with their New Year's resolution in full force....until they become lethargic, apathetic, or just plain distraught. Often purchasing brand new attire/equipment from the latest store to fit the part. May even preach to others about their new-found zest for life in the two weeks that they are, in fact, taking part in making their resolution, a success.
"Man, the track is full of resolutionaries this morning...I'll give them two weeks".
Those people crowding the gym during the first few weeks of January.
The gym was too full of resolutionaries for me to work out today, but it should be better by February.