Low-key, originally refers to low-key, metaphorical tone is mild or relatively depressed. Later, he described it as peaceful, but not ostentatious. It is also a new network language, which is popular in life. Keeping a low profile means hiding your abilities and not showing them. Keeping a low profile doesn't mean not doing things well, but not showing off what you have done well. Low-key, sometimes used for seal cutting and calligraphy creation.
The antonym of low-key meaning is high-key, and the antonym of metaphor is arrogance.