This is the 914th most frequent Chinese word.
锻炼
To exercise or to engage in physical training.
In this sentence, "锻炼" is used as a verb meaning 'to exercise' or 'to work out', referring specifically to physical activity.
我每天早晨都会锻炼身体。
I exercise my body every morning.
Here, "锻炼" metaphorically means 'to train or develop,' applied to a mental or character trait like willpower.
这个工作是锻炼一个人意志的好机会。
This job is a great opportunity to train a person's willpower.
In this example, "锻炼" is used in the sense of 'to practice or hone,' referring to improving skills.