昧 mui⁶ {mèi}

1. to conceal
2. dark

昧水 mui⁶ seoi² {mèi shuǐ}

to dive

昧旦 mui⁶ daan³ {mèi dàn}

the time just before daybreak

昧沒〔-没〕 mui⁶ mut⁶ {mèi mò}

1. veiled
2. obscure

昧心 mui⁶ sam¹ {mèi xīn}

against one's conscience

昧死 mui⁶ sei² {mèi sǐ}

to risk one's life

昧良心 mui⁶ loeng⁴ sam¹ {mèi liáng xīn}

it goes against one's conscience

昧水舂牆〔---墙〕 mei⁶ seoi² zung¹ coeng⁴ {mèi shuǐ chōng qiáng}

to dive under water hitting walls, to describe someone is very determined, going through hurdles and hardships