She meant to take her in the carriage, leave her at the Abbey Mill, while she drove a little farther, and call for her again so soon, as to allow no time for insidious applications or dangerous recurrences to the past, and give the most decided proof of what degree of intimacy was chosen for the future.
At this moment, an ingenious and animating suspicion entering Emma’s brain with regard to Jane Fairfax, this charming Mr. Dixon, and the not going to Ireland, she said, with the insidious design of farther discovery, "You must feel it very fortunate that Miss Fairfax should be allowed to come to you at such a time.
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The debt grew insidiously—just a little at a time and always for a good purpose.
Alan Greenspan -- The Age of Turbulence
We’ve grown accustomed to spending more than we earn, but the increasing debt is an insidious problem.