冇

冇 (Kangxi radical 13, 冂+2, 4 strokes, cangjie input 大月 (KB) or 難大月 (XKB), four-corner 4022₇, composition ⿸𠂇冂)

• 𪢹, 𱥲, 𭁤, 𭁬, 𠕆, 𠕇

• Kangxi Dictionary: not present, would follow page 128, character 35
• Hanyu Da Zidian (first edition): volume 1, page 96, character 17
• Unihan data for U+5187

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• 冇 (Cantonese)

From the removal of the two inner strokes from 有 (“to have”).

Attested at least since 1672, in 《星餘筆記》 by 王鉞:

From 無 (MC mju, “to not have”). In some varieties, such as Cantonese and Xiang, there seems to be fusion or analogy with 有 (MC hjuwX, “to have”) (Chan, 1998; Schuessler, 2007).

冇

1. (dialectal Mandarin, Cantonese, dialectal Gan, Hakka, dialectal Wu, Xiang) to not have; to not exist

   • 你冇女朋友？梗係唔信啦！……或者有。你唔知啫。 [Cantonese, trad.]
     你冇女朋友？梗系唔信啦！……或者有。你唔知啫。 [Cantonese, simp.]

     From: 陳慧嫻, 紅茶館

     nei⁵ mou⁵ neoi⁵ pang⁴ jau⁵? gang² hai⁶ m⁴ seon³ laa¹!...... waak⁶ ze² jau⁵. nei⁵ m⁴ zi¹ ze¹.

     You don't have a girlfriend? Of course I don't believe you! ... Maybe you do have one, but you just don't know it.

   冇理由㗎。 [Cantonese]  ―  mou⁵ lei⁵ jau⁴ gaa³.   ―  Impossible.

2. (dialectal Mandarin, Cantonese, Xiang) have not; did not (do something) (indicating non-completion of a verb)

   我冇同佢講。 [Cantonese, trad.]
   我冇同佢讲。 [Cantonese, simp.]

   ngo⁵ mou⁵ tung⁴ keoi⁵ gong².

   I did not tell him.

   佢幾個月都冇嚟。 [Cantonese, trad.]
   佢几个月都冇嚟。 [Cantonese, simp.]

   keoi⁵ gei² go³ jyut⁶ dou¹ mou⁵ lai⁴.

   He hasn't come for a few months.

3. (dialectal Cantonese, Nanning Pinghua) not (negator)

   冇手尾 [Nanning Pinghua]  ―  me⁵ sau² mi⁵ [Jyutping++]  ―  irresponsible

• Originally from Cantonese, many Mandarin speakers now understand the meaning of this character.

Compare Saek (phoong^C2, “hollow; hole (in a tree, bamboo)”), Proto-Bahnaric *pɔːŋ (“hollow; flattened”) (Schuessler, 2007).

This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.