The Italian term "inadatto, incapace" matches the English term "unable"

other italian words that include "inadatto" : english :
inadatto, incapace incapable
inadatto, inabile al lavoro, disadatto unfit
other italian words that include "incapace" : english :
inadatto, incapace incapable
inefficiente, incapace inefficient
incapace al lavoro unfit for work