to weaken the cottage, confidence, self-discipline etc of (e.g. an army)

depress, unnerve

(to try) to take away the courage or confidence of (a person)

dishearten, dispirit

cause (a person) to lose courage or confidence

depress, ruin one's hopes

(to cause a person) to feel sad

upset, depress

(to cause a person, animal) to become weary, in need of rest etc

exhaust, weary