一笔不苟

yī bǐ bù gǒu

lit. not even one stroke is negligent (idiom)

fig. to write characters (calligraphy) in which every stroke is placed perfectly

一

yī

one

笔

bǐ

writing brush; writing implement (pen, pencil etc) (CL:支[zhi1],枝[zhi1])

不

bù

no; not so

苟

gǒu

(literary) if indeed