nag at

nag at (one)

To lecture or reprimand one in an annoying, pestering manner, especially about something one considers minor, trivial, or inconsequential. Would you stop nagging me already? I'll do the dishes later! Look, I don't like having to nag you about this, but those reports really need to be filed today.
See also: nag
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

nag at someone (about someone or something)

to pester someone about someone or something. Don't keep nagging at me about her. Stop nagging at me!
See also: nag
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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References in periodicals archive ?
The e-mail carries three news items released by NAG at the Supercomputing 2010 show.
According to the dictionary, to nag at someone means to be a constant source of discomfort or worry, which is not very nice at all.