literal: honor without return
translated: without hesitation, without turning back
义
yì
justice, righteousness
无
wú
not, without
反顾
fǎngù
look back, turn back
反
fǎn
flip, return, reverse
顾
gù
to reach, to rival
毛不易 - 给你给我
Mao Buyi - Gei Ni Gei Wo
给你我义无反顾的长长和久久
Gěi nǐ wǒ yìwúfǎngù de chāngchāng hé jiǔjiǔ
(I'll) give you my eternity, without once glancing back
In this lyric, the idiom helps express the singer's enthusiasm and dedication. In the context of the song, he promises that he will remain devoted forever without wavering in his commitment.