infestuous
Mischievous; harmful; dangerous.
The Store-houses burnt, the siege harde plyed, the waste of victuals great, the husbanding of them none at all, there fell such an infestuous unsaciable famine amongst them, that if all the stones of Jerusalem had been bread, and they should have tyred on them, yet woulde they have beene behind hand with their appetite.
1593, Thomas Nashe, Christs Teares over Jerusalem, London: Andrewe Wise, Ronald B. McKerrow (editor), The Works of Thomas Nashe, London: A.H. Bullen, 1904, Volume 2, p. 69,
Where it comes from
From Latin infestus. See infest (adjective). By surface analysis, infest + -u- + -ous.
Adapted from the Wiktionary entry infestuous (CC BY-SA 4.0).