X(也)不是，不X也不是 and X也X不…，Y也Y不…: no way out
【高131】【高134】口语格式 / fixed patterns
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
X(也)不是，不X也不是 paints a dilemma: doing X is wrong, and not doing X is wrong too. 走不是，不走也不是 ("leaving is no good, staying isn't either"), 笑也不是，不笑也不是. It is the Chinese "damned if I do, damned if I don't". The second half negates the same verb and keeps its 也, while the first 也 is optional (走不是). HSK 5 already introduced the family X也不是，Y也不是 (哭也不是，笑也不是); here the second term is always the negation of the first.
X也X不C，Y也Y不C (C = the complement) says that every attempt fails: the verb is repeated on both sides of 也 and 不 is followed by a result complement, that is, a potential complement (吃不下, 睡不着, 谈不拢, 劝不动). 吃也吃不下，睡也睡不着: "I can't eat and I can't sleep". It is no longer a moral dilemma but helplessness: circumstances, or a person, won't give. Do not confuse it with 吃也吃不得 of HSK 5, where 不得 expresses a ban: here the complement just says it doesn't work.
Both moulds are spoken and expressive. They often come after a remark (弄得……, 真让人……, 急得……) and show the speaker's exasperation or embarrassment; they would be out of place in an official text.
Examples
大家都盯着我，我走也不是，不走也不是。
Dàjiā dōu dīngzhe wǒ, wǒ zǒu yě bú shì, bù zǒu yě bú shì.Everyone was staring at me; leaving was wrong, and staying was wrong too.
他当众拿我开玩笑，我笑也不是，不笑也不是，真尴尬。
Tā dāngzhòng ná wǒ kāi wánxiào, wǒ xiào yě bú shì, bú xiào yě bú shì, zhēn gāngà.He teased me in front of everybody; laughing was wrong and not laughing was wrong too. So awkward.
会开到一半，他们俩吵了起来，我走不是，不走也不是，只好低头看手机。
Huì kāi dào yíbàn, tāmen liǎ chǎo le qǐlai, wǒ zǒu bú shì, bù zǒu yě bú shì, zhǐhǎo dī tóu kàn shǒujī.Halfway through the meeting the two of them started arguing; leaving felt wrong and staying felt wrong too, so I looked down at my phone.
这条路堵得厉害，进也进不去，退也退不出来。
Zhè tiáo lù dǔ de lìhai, jìn yě jìn bu qù, tuì yě tuì bu chūlái.This street is so jammed you can neither get in nor back out.
这几天心里有事，我吃也吃不下，睡也睡不着。
Zhè jǐ tiān xīnli yǒu shì, wǒ chī yě chī bu xià, shuì yě shuì bu zháo.I've had something on my mind lately; I can't eat and I can't sleep.
他的脾气太倔，劝也劝不动，拦也拦不住。
Tā de píqi tài juè, quàn yě quàn bu dòng, lán yě lán bu zhù.He is so stubborn that talking to him gets nowhere and nothing can hold him back.
Common mistakes
✗ 走也不是，不走不是。 → ✓ 走也不是，不走也不是。 (the second half keeps its 也; only the first may drop it: 走不是，不走也不是).
✗ 吃也吃不，睡也睡不。 → ✓ 吃也吃不下，睡也睡不着。 (after 不 a result complement is needed: 不下, 不着).
✗ 劝也不动，拦也不住 → ✓ 劝也劝不动，拦也拦不住 (the verb is repeated before 不 + complement).