理直氣壯（理直氣壯）　

◎ 理直氣壯 lǐzhí-qìzhuàng

[be in the right and selfconfident;be self-confident on the strength of one‘s being right;justly and forcefully; speak with compelling argument] 理由充分,言行因而有氣勢(shì)

只要我們理直氣壯,怕他怎的!