no earthly reason

no earthly reason

No conceivable or practical reason. You had all day, so there's no earthly reason you couldn't have finished this on time! It's very sweet that you bought me a laptop, dear, but I'm 85—I have no earthly reason to use one of those things!
See also: earthly, no, reason
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

no earthly reason

no conceivable reason. There is no earthly reason for your rude behavior. I can think of no earthly reason why the repairs should cost so much.
See also: earthly, no, reason
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

no earthly reason

n. no conceivable reason. I can think of no earthly reason why the repairs should cost so much.
See also: earthly, no, reason
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
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References in periodicals archive ?
I can see no earthly reason why taxpayers, via the benefits system should fund the retirement income of buy-to-let landlords.
Speaking at the National Eisteddfod in Bala yesterday, the veteran politician insisted there is "no earthly reason" why the vote on the next step of devolution cannot take place next year.
"There is no earthly reason why M15 and GCHQ should have a reason to bribe people," Labour MP, Andrew MacKinlay added.
Of course, it could be otherwise, for there is no earthly reason why we should have to continue with our Cinderella care services or why we should have to put up with poor inner-city housing, education and health services.
A tabloid snapper has been shot, but the plot is full of red herrings, outrageous coincidences and crucial evidence being withheld for no earthly reason.
The simple answer is because there is no earthly reason to capitalize any of these words.
They are part of the campaign to disprove the earthly existence of Christ, something I refuted in my 'No Earthly Reason To Disbelieve' in Christian Courier, Nov.
But there is no earthly reason why they can't put it back into the health system where it is badly needed.