ad. 说不出地(难以形容地)

[ adv ]
to an inexpressible degree
<adv.all>
she was looking very young tonight, and, as usual, indescribably beautiful, in a simple strapless dress of a green and white silky cotton

Unspeakable \Un*speak"a*ble\, a. [Pref. un- not + speakable.]
Not speakable; incapable of being uttered or adequately
described; inexpressible; unutterable; ineffable; as,
unspeakable grief or rage. -- {Un*speak"a*bly}, adv.

Ye rejoice with joy unspeakable and full of glory. --1
Pet. i. 8.