Disqualify
Part of speech: verb
Definition: To make ineligible for something, by the explicit revocation of a previous qualification.
Unfit
Part of speech: adjective
Definition: Not fit; not having the correct requirements.Not fit, not having a good physical demeanor.
Part of speech: verb
Definition: To make unfit; to render unsuitable, spoil, disqualify.
Example sentence: Mistresses are like books; if you pore upon them too much, they doze you and make you unfit for company; but if used discreetly, you are the fitter for conversation by em.