His one big failing is that he never says he's sorry.他的一大缺点是从不肯道歉。
failing
prepositionuk/ˈfeɪ.lɪŋ/us/ˈfeɪ.lɪŋ/
如果不行，若无
if that is not possible
Buy her some flowers, or failing that, just send her a card.给她买一些花吧，实在不行，就寄一张卡去。
Appointments are available on the 2nd and the 6th of this month but failing either of those, we could fit you in on the 15th.本月2号和6号可以预约，如果都不行，我们可以为您安排在15号。
failing
adjectiveuk/ˈfeɪ.lɪŋ/us/ˈfeɪ.lɪŋ/
衰退中的；逐渐减弱的；渐趋失败的
becoming weaker or less successful
a failing business日渐衰败的企业
failing eyesight衰退的视力
In the failing light, it was hard to read the street signs.天色渐暗，难以看清路标。