Overlightly

A prudent man doth not overlightly beleeve any thing, but laieth aside all reputation and credit of him that speaketh, and examineth the speech by it selfe: […]

Source: wiktionary

Mrs. Burton's conscience smote her not overlightly, and she hastened to change the subject, and to devote herself assiduously to Budge, as if to atone for some injury which she might have done to his brother.

Source: wiktionary

In short, it is said to do more for builders than agriculturists, and has been, let us hope, overlightly named " The Freemasons' Refuge."

Source: wiktionary

I have heard it said that in these days young people speak overlightly of divorce.

Source: wiktionary