un·fit 
(ŭn-fĭt)
(ŭn-fĭt)adj.
1. Not meant or adapted for a given purpose; inappropriate: a solvent that is unfit for use on wood surfaces.
2. Below the required standard; unqualified: an unfit parent.
3. Not in good physical or mental health.
4. Biology Unable to survive or produce viable offspring in a particular environment.
tr.v. un·fit·ted, un·fit·ting, un·fits
To cause to be unsuited or unqualified: "Having run for president ... often unfits a man for lesser or more useful subsequent work" (Garry Wills).
un·fitly adv.
un·fitness n.