The word "more lessened" means to decrease gradually or become smaller. The antonyms for this would be to increase or to grow. If something is growing or increasing, it is getting bigger, greater or more significant over time. For instance, the team's morale might have increased after receiving the good news about their project. Alternatively, the amount of rainfall could be growing day by day around a certain region. Hence, the word "more lessened" has opposite meanings which are to increase or to grow.