cỏ

From Proto-Vietic *kɔh (“grass”).

• (Đông Kinh) [kɔ^C1]

cỏ (𦹵, 𦹯, 苦)

1. grass

   sang cỏ (cây cỏ) ― flora

• muâng cỏ
• ma cỏ

• Alexandre de Rhodes (1651) “cỏ”, in Dictionarium Annamiticum Lusitanum et Latinum (in Middle Vietnamese, Latin, and Portuguese), Rome: Propaganda Fide

From Middle Vietnamese cỏ, from Proto-Vietic *kɔh (“grass”). Cognate with Thavung ก็อฮ.

The sense "marijuana" is probably a calque of English weed.

• (Hà Nội) IPA^(key): [kɔ˧˩]
• (Huế) IPA^(key): [kɔ˧˨]
• (Saigon) IPA^(key): [kɔ˨˩˦]

• Audio (Saigon):

  (file)

(classifier lá, cây, ngọn) cỏ • (𦹵, 𦹯, 古, 苦)

1. grass
2. (slang) weed; marijuana

• Usage of the classifier ngọn is literary.

cỏ • (𦹵, 𦹯, 古, 苦)

1. (literary) negligible

• "cỏ" in Hồ Ngọc Đức, Free Vietnamese Dictionary Project (details)
• Lê Sơn Thanh, "Nom-Viet.dat", WinVNKey (details)