理直气壮（理直氣壯）　

◎ 理直气壮 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,言行因而有气势

只要我们理直气壮,怕他怎的!