From Longman Dictionary of Contemporary Englishbe no slouch (at something)be no slouch (at something)informalGOOD AT to be very good at something Horowitz was no slouch at languages. → slouch
Examples from the Corpus
be no slouch (at something)• Reed, 33, is no slouch in the kitchen herself.• Bonds were no slouch, either.• Shearer is some talent, but Newell & Gallagher are no slouches.• Your engineer officer, McCafferty, is no slouch either and neither is mine.• At 12-1, Stanford is no slouch at home either, you know. 