Simple past tense and past participle of flounder.
Floundered Sentence Examples
She floundered to a sitting position, then her feet, cringing as she struggled upright, the sting in her wounded knees bringing tears to her eyes.
He'd floundered up until now.
Dorothy was a little anxious about the success of their trip, for the way Jim arched his long neck and spread out his bony legs as he fluttered and floundered through the air was enough to make anybody nervous.
In 2007, Kelly launched the Double Up tour featuring Ne-Yo and Keisha Cole, but that tour, like his career, floundered.