This reminds me of
Keep Your Identity Small from Paul Graham.
Which incidentally also seems to match the translation you gave: Don't take on a role. Or don't be bound by the role you (identity) take on.
Wuwei (kanji: 無為, simplified: 无为, pinyin: wúwéi, hiragana: むい) denotes a political philosophy and a state of mind.
Wuwei combines wu 無 and wei 為. Wu is straightforward to translate. Wu means "don't" or "without". Wei is not straightforward to translate. I like to think of wei as "action" or "intention". The CC-CEDICT project defines wei in terms of performing a capacity. That is, to become by doing i.e. to take a role.
為 为 [wei2] /as (in the capacity of)/to take sth as/to act as/to serve as/to behave as/to become/to be/to do/by (in the passive voice)/
The political philosophy of wuwei can be crudely translated into "self-government".
In eastern political philosophy, the emperor is above running the government. The actual job of running the government is his ministers' responsibility. If anything goes wrong then it is the ministers' fault. If the emperor does make a proclamation then it should be vague and abstract. If things go right then it is due to the emperor's wise leadership. If things go wrong then it is the fault of corrupt incompetant bureaucrats. The emperor leads indirectly, by setting a example of model behavior.
"I will punish the bird if it does not sing," said Nobunaga.
"I will reward the bird it it does sing," said Hideyoshi.
Tokugawa waited for the bird to sing.
The wuwei state of mind is analogous to wuwei statecraft. It is the idea that the best way to act is by letting yourself act instead of compelling yourself to act.