Simple past tense and past participle of blether.(verb)
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Use "blethered" in a sentence
"She blethered on while Bill sipped his fortified tea and Joanne warmed herself by the fire."
"He kept talking about "tough choices" and "difficult decisions" but as far as I could tell he didn't answer a single one of John Humphries questions, he just blethered on about Tory cuts whilst failing to acknowledge that Labour will on their own figures have to cut too."
"She blethered for ages and ages and ages on the second question."