刀枪不入

dāo qiāng bù rù

lit. impervious to sword or spear (idiom)

fig. invulnerable; untouchable; thick-skinned; impervious to criticism

刀

dāo

knife; blade; single-edged sword; cutlass (CL:把[ba3])

枪

qiāng

variant of 槍|枪[qiang1]

不

bù

no; not so

入

rù

to enter; to go into