Simple past tense and past participle of backslide.(verb)
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Use "backslid" in a sentence
"All Tech must do is beat Wake Forest, which has backslid this season, and Duke, which has progressed from lousy to so-so, and it's in the ACC title game, where it will meet ..."
"And while even Tuck was wary of making any grandiose "turned-the-corner" statements about an 8-7 team that's multiple times seemed to have turned that corner and then backslid, he did say, "I think we are poised to make a run.""
"That the Republicans in Congress backslid (and were pushed in that direction by a big government GWB) is no fault of the principles themselves."