なきにしもあらず
な
き
に
し
も
あ
ら
ず
Meanings
1
not non-existent; there is some; not completely lacking
usually written using kana alone
A formal, somewhat literary expression meaning that something does exist to some degree, often used to acknowledge a possibility or a small amount. It is a double-negative construction (無き + にしもあらず) that softens the assertion.
There is certainly some room for improvement.
His argument is not entirely without merit.