plounce
/plaʊns/Now rare (English regional in later use)
verb
1 [with object] To plunge or submerge in water; (in early use especially) to plunge into water as a punishment, to duck.
2 [no object] To plunge in or into water, mud, etc.; to flounder or wallow.
Origin
Mid 17th century. Apparently a variant of plunge; perhaps a blend of plunge and flounce.