"hammer" is the Chinese term for a kind of physical tool used in construction work. It can also mean something that is hard or tough, which might be used to describe someone who is quick and efficient at making things difficult or complicated. "hammer" can refer to both positive (as when it's used to describe a person) and negative (as when it's used to describe someone). However, in this context, the word 'hammer' means something that's hard to make progress on and requires a lot of effort. If you're feeling stuck or overwhelmed, the hammer can be a helpful tool for overcoming those obstacles.