exertion

noun
1
physical or mental effort; the act of making an effort
تلاش, کوشش, زحمت
2
the use of power to make something happen
استفاده از نیرو, به‌کارگیری توان, اعمال
the exertion of force/strength/authority
It requires no great exertion of the imagination to recognize the truth of this.