bù dàng
unsuitable
improper
inappropriate
huǐ bù dāng chū
to regret one's past deeds (idiom)
bù dàng yī huí shì
not regard as a matter (of any importance)
bù dāng shì
useless
regard as useless
bù dāng jǐn
not important
of no consequence
shuō huà bù dàng huà
to fail to keep to one's word
to break a promise