Verb

(undermin)

To dig underneath (something), to make a passage or for destructive or military purposes; to sap.

* 2009 , (Diarmaid MacCulloch), A History of Christianity , Penguin 2010, p. 312:

Martin, for instance, had on one occasion undermined a tree sacred to old gods, then stood in the path of its fall, but forced it to fall elsewhere by making the sign of the Cross.

(figuratively) To weaken or work against; to hinder, sabotage.

* {{quote-news, year=2012, date=April 19, author=Josh Halliday, work=the Guardian

, title= Free speech haven or lawless cesspool – can the internet be civilised? , passage=The growing use of social media to spread anger and dissent in the Arab world has been hailed by western governments as one of the chief justifications for a completely unfettered internet. The US is reportedly funding the secret rollout of technology in Iran in an effort to undermine internet censors in the country.}}

Verb

(mitigat)

To reduce, lessen, or decrease.

* 1795 —

Measures are pursuing to prevent or mitigate the usual consequences of such outrages, and with the hope of their succeeding at least to avert general hostility.

* 1813 —

But in yielding to it the retaliation has been mitigated as much as possible, both in its extent and in its character...

* 1896 —

Then they tell us that vaccination will mitigate the disease that it will make it milder.

* 1901 — , ch 7

Then I discovered the brilliance of the landscape around was mitigated by blue spectacles.

* 1920 —

The plague had not been kind to him, yet had left him this small furry thing to mitigate his sorrow; and when one is very young, one can find great relief in the lively antics of a black kitten.

To downplay.