Exerting freely describes painting, writing, and composing, and you can use your pen as you please.
Source: Chapter 25 of "Niehaihua" by Zeng Pu of the Qing Dynasty: "My family gave me a pen filled with ink. Jue Zhai picked up the pen and wrote more than a hundred words freely on the paper. Word."
Usage: subject-predicate; used as predicate and attributive; with a complimentary meaning.
Synonyms: imaginative, flawless, easy to use, handy, well-trained, and so on.
Extended information:
Synonyms
天马行空 [tiān mǎ xíng kōng]?
Metaphor for being bold and unrestrained (mostly used in Evaluate aspects of writing, painting, calligraphy, etc.). Tianma: The sweat-blooded horse obtained from Dawan (the name of the country in the ancient Western Regions) during the reign of Emperor Wu of the Han Dynasty is called Tianma, which means divine horse. See "Historical Records·Biography of Dawan". Xingkong: describes a galloping horse, like flying in the sky. It is also used to describe remarks that are vague and irrelevant.
Source: "Preface to the Collection of Poems of Sa Tianxi" by Liu Tingzhen of the Yuan Dynasty: "The reason why it is deified and transcends all other forms is probably like a horse flying in the sky with extraordinary steps."
Translation: Therefore it can Supernatural and extraordinary, almost like a Pegasus walking on the air with extraordinary steps.