Emily Dickinson Lexicon

IN-FECT', v.t. [Fr. infecter; Sp. infectar; It. infettare; L. inficio, infectus; in and facio. In this application of inficio, as in inficior, to deny, we find the radical sense of facio, to make, which is to thrust, to drive. To infect, is to thrust in; to deny is to thrust against, that is, to thrust away, to repel. And here we observe the different effects of the prefix in, upon the verb.]

1. To taint with disease; to infuse into a healthy body the virus, miasma, or morbid matter of a diseased body, or any pestilential or noxious air or substance by which a disease is produced. Persons in health are infected by the contagion of the plague, of syphilis, of small pox, of measles, of malignant fevers. In some cases, persons can be infected only by contact, as in syphilis; in most cases, they may be infected without contact with the diseased body.
2. To taint or affect with morbid or noxious matter; as, to infect a lancet; to infect clothing; to infect an apartment.
3. To communicate bad qualities to; to corrupt; to taint by the communication of any thing noxious or pernicious. It is melancholy to see the young infected and corrupted by vicious examples, or the minds of our citizens infected with errors.
4. To contaminate with illegality.