Regarding the two reduplicated words "chăm chỉ" (diligent) and "chăm chú" (attentive).

"Chăm chỉ" and "chăm chú" are included and defined in the Dictionary of Reduplicated Words in Vietnamese (Institute of Linguistics). In this article, we will analyze the coordinate meanings of "chăm chỉ" and "chăm chú". (The text in quotation marks after the entry number is the original text from the Dictionary of Reduplicated Words in Vietnamese - Institute of Linguistics - edited by Hoang Van Hanh; the new line is our discussion):

1. "Diligence (in general terms). Diligence in studying."

"Chăm chỉ" is a compound word with coordinate structure [historical meaning], in which both constituent elements are of Chinese origin. The Chinese word "chăm" comes from the character 耽 (dān), meaning to love, to be attentive, to stare intently (as in 耽耽 (dān dān) = to be attentive; 虎視耽耽 (hǔ shí dān dān) = to stare intently like a tiger); when Vietnameseized (dān → chăm), it means to always pay attention to something (as in caring; diligently working, industrious, dedicated); 砥 (zhǐ), is a Chinese element signifying the act of sharpening, training, and self-cultivation. The Chinese Dictionary defines the third meaning of "zhǐ" as: "to sharpen, to cultivate" and suggests referencing the words 砥節 (shrinking one's character) and 砥礪 (shrinking, refining).

The relationship D ↔ CH (dam ↔ cham) can also be seen in many cases such as: dam 潭 ↔ cham (cham bai); dam 壜 ↔ chum (chum vai); diem 點 ↔ dot; diep 疊 ↔ chap/trap (chap chung/trap trung),...

In the word "chăm chỉ" (diligent/hardworking), "chăm" has the ability to stand independently in its function (Because he diligently works in farming/ That's why he has a basket inside and a bag outside - Folk song); while "chăm" is merely a dependent element of Chinese origin, incapable of standing independently.

2. "Pay close attention. Focus your attention or show intense interest in an object. Listen attentively to a lecture. Look intently."

"Chăm chú" is a compound word with coordinate meanings: "chăm" is of Chinese origin, derived from the character 耽 (dàn) meaning to stare intently (as we analyzed and demonstrated in the section on "diligence"); "chú" 注 means to concentrate, to focus on a task (as in "chú tâm" 注心; "chú ý" 注意; "chuyên chú" 專注; "chú mắt cái điện thoại").

Reference: The Vietnamese dictionary of the Association for the Advancement of Knowledge and Virtue defines "chú" as "to pour. Figurative meaning: to pay close attention to (not used alone)". However, in practice, "chú" is still used alone (independently in function), for example: All day long, he only focuses his eyes and nose on the phone. The Thanh Nghi dictionary gives a very clear example: "chú • verb. To pour (itd); figurative meaning. To pay attention, to be diligent <> He only focuses on that one thing, and doesn't care about anything else."

Thus, both words "chăm chỉ" (diligent) and "chăm chú" (attentive) are composed of elements of Chinese origin. "Chăm chỉ" is a compound word with coordinate structure (meaning it was used throughout different eras), while "chăm chú" is a compound word with coordinate structure (meaning it was used both times). Because both constituent elements, "chăm" and "chú," can function independently, "chăm chú" is a compound word, not a reduplicated word.

Man Nong (Contributor)

Source: https://baothanhhoa.vn/ve-hai-tu-lay-nbsp-cham-chi-va-cham-chu-280679.htm