Submissionist was a derogatory term used by Southern secessionists in the year preceding the American Civil War to describe Southerners who wanted to preserve the Union.
Before 1861, Southerners loyal to the Union were generally respected as principled idealists.
Consequently, "submissionist" was a derogatory name for a Southerner who would seemingly relinquish sovereignty in order to remain in the Union.
[1] The term was used also to describe a particular kind of cooperationist, that is, those who were generally opposed to secession; Louisiana politician Pierre Soulé, for instance, a cooperationist, protested that he was "no submissionist" and would choose revolution (i.e., secession) rather than ignominy.
[3] Edmund Ruffin, who is credited with firing the first shot at the Battle of Fort Sumter, noted in his diary, September 3, 1861, "As a general rule, the Submissionist party embraces, & is largely composed of, the old, the timid, the cowardly, the imbecile & the mean-spirited.