Synonym of FLOUNDER

Run : move at a speed faster than a walk, never having both or all the feet on the ground at the same time.
Fluctuate : rise and fall irregularly in number or amount.
Jump : push oneself off a surface and into the air by using the muscles in one's legs and feet.
Stumble : trip or momentarily lose one's balance; almost fall.
Flounder : struggle or stagger clumsily in mud or water.

Synonym of Flounder is Stumble