Mortíferous. adj. [mortifer, Latin.] Fatal; deadly; destructive.

What is it but a continued perpetuated voice from heaven, to give men no rest in their sins, no quiet from Christ's importunity, till they awake from the lethargick sleep, and arise from so dead, so mortiferous a state, and permit him to give them life. Hammond's Fundamentals.

These murmurings, like a mortiferous herb, are poisonous even in their first spring. Government of the Tongue, s. 10.