Zazen in Chinese / Japanese...

坐禪 describes the act of sitting in a state of deep meditation.

You'll notice that the second character is Chan/Zen (often used to title the meditative form of Buddhism).

In Korean Hanja, this means “religious meditation” (roughly the same as the Chinese definition).

Buddhists may define this as sitting in dhyāna, abstract meditation, fixed abstraction, or contemplation.

Japanese note: This will make sense in Japanese but the Kanji shown to the left are partially in ancient/traditional Japanese form. Japanese Buddhists may use 坐禪, 坐禅, 座禪, or 座禅. The most standard/modern Japanese form of this word is shown to the right. Click on the Kanji to the right (instead of the button above) if you want this specifically Japanese version.

Hishiryō (非思量) literally means not-thinking.

Hishiryo can be described as a state of mind beyond thinking and non-thinking during the practice of Zazen.

Shiryō (思量) means “thinking,” and hi (非) is a prefix for negation and opposition.

Therefore, hishiryo amounts to “unthink” or “not the matter of thinking.” The word hishiryo appears in Dogen Zenji’s Fukanzazengi, Shobogenzo Zazengi, Shobogenzo Zazenshin, and Keizan Zenji’s Zazen Yojinki. It is one of the most important words used to describe zazen. Hishiryo in these writings comes from a dialogue between Yakusan Igen (745-828) and an unnamed monk, which is described in Keitoku, Dentoroku, and other Zen texts.

The above is an abridged except from School of Shodo: Hishiryo
I suggest you visit that page for a full explanation.

接心 is a Japanese Buddhist term meaning concentration or a period of intensive zazen.

While 接心 is the most common way to write this, other variants include 攝心 (Traditional Chinese), 摂心 (alternate Japanese), and 摄心 (Simplified Chinese). If you need any of these alternate forms, just let me know and I will set it up with the calligrapher for you.

While this is a Japanese term, it will be recognized by most Chinese folks at a Japanese Buddhist term and they will pronounce it as “jiē xīn” in Mandarin.

只管打坐 is the Japanese Buddhist term shikantaza which represents zazen meditation in which one focuses on sitting without actively seeking enlightenment.

Sometimes this is translated as “meditation of just sitting” or “meditation practice where one stays intensely focused without focusing on any particular object.”

Sometimes written, 祗管打坐 with the same pronunciation and perceived meaning.