i Register
In some senses, cowardize is marked as obsolete. Watch for register when choosing this word.
noun
Obsolete spelling of cowardice.
The ſecond property of your excellent ſherris, is the vvarming of the blood, vvhich before (cold & ſetled) left the lyuer vvhite & pale, vvhich is the badge of puſilanimitie and covvardize: but the ſherris vvarmes it, and makes it courſe from the invvards to the partes extreames, […]
verb
To render (someone or something) cowardly, to cause to become a coward.