(of a thing) not of the necessary quality or standard to meet a particular purpose

the land is unfit for food crops

(of a person) not in good physical condition, typically as a result of failure to take regular exercise

the increase in the number of unfit and overweight children is alarming

make (something or someone) unsuitable; disqualify

they say that we are trying to give poor children tastes which will only unfit them for a life of hardship and toil