3 adjectives to describe underminings

He saw in the bold philosophical speculations of Descartes, Malebranche, Spinoza, Leibnitz, and Locke an insidious undermining of the doctrines of the Church, an intellectual freedom whose logical result would be fatal alike to Church and State.

A proof worthy of the manly mind of Luther, and compared with which the Grotian pretended demonstrations, from Grotius himself to Paley, are mischievous underminings of the Faith, pleadings fitter for an Old Bailey thieves' counsellor than for a Christian divine.

It were needless now to tell of all the secret underminings of life's hidden springs.

3 adjectives to describe  underminings