vô + Noun

To become proficient in using vô-, you must understand its morphological rules and how it contrasts with other negators:

• The '-less' Equivalent: It is often the exact equivalent of the English suffix '-less' (e.g., vô dụng = useless, vô tận = endless). Crucial Note: Be careful with the word for "price/value". Vô giá means "priceless" or "invaluable" (a high compliment), whereas vô giá trị means "worthless" or "invalid" (an insult). Do not mix these up!
• Attachment: It attaches primarily to Sino-Vietnamese vocabulary roots. However, there is a notable exception: it frequently attaches to native Vietnamese words to express limitlessness or countlessness (e.g., vô kể, vô bờ, vô vàn), a meaning also shared by many Sino-Vietnamese compounds (e.g., vô hạn, vô tận). Because Vietnamese is an isolating language, it does not cause any phonological changes and, like all syllables, is written as a separate syllable, separated from the root by a space.
• Register: While Sino-Vietnamese words often belong to formal or academic registers, many vô- compounds have completely integrated into casual, everyday spoken Vietnamese (e.g., vô duyên [tactless], vô tư [carefree]).
• Adverb of Degree: You will frequently encounter the compound vô cùng (infinitely / extremely), which functions as one of the most common adverbs of degree in Vietnamese. Unlike some other degree words, it can be placed either before or after the adjective (e.g., vô cùng đẹp or đẹp vô cùng).
• Contrasting Prefixes:
  - bất- (prefix) means "un-" or "not" and negates an adjective, state, or verb (e.g., bất công = unfair, bất tuân = to disobey).
  - phi + X means "non-" and indicates exclusion from a category (e.g., phi chính phủ = non-governmental).
  - vô- means "without" and indicates lacking a noun/entity (e.g., vô kỷ luật = without discipline), or the absence of an action or state when attached to verbs (e.g., vô học = uneducated, vô tri = inanimate / mindless).
• The Antonym 'hữu-': The direct Sino-Vietnamese antonym of vô- is hữu- (with / having). They form common opposite pairs in everyday vocabulary (e.g., vô hình [invisible] vs. hữu hình [visible]; vô ích [useless] vs. hữu ích [useful]).

Important Note: Do not confuse the prefix vô- with the Southern Vietnamese native verb/preposition vô, which means "to enter" or "into" (the equivalent of Northern vào). Additionally, vô (often pronounced and spelled as dzô or dô) is the universal Vietnamese drinking cheer (e.g., Một, hai, ba, vô!).