From Longman Dictionary of Contemporary Englishplug away phrasal verbWORK HARDto keep working hard at something at If you keep plugging away at it, your English will improve. → plug→ See Verb table
Examples from the Corpus
plug away• In any case, Fred worked, worried, plugged away.• Said later that he s an exceptional talent and only bad luck stopped him scoring, and to keep plugging away.• He's gone about it quietly, just plugging away and learning from watching others.• Ian plugged away at the lab that was to become Roslin, trying to improve the technology of animal transgenesis.• But as Sulloway was plugging away, other scientists were busy debunking birth order.• An ideal adventure for beginners, this one should have you plugging away till the wee small hours of the morning.plug at• We need to find out where we can improve, and keep plugging away at it.• Ian plugged away at the lab that was to become Roslin, trying to improve the technology of animal transgenesis. 