Inexpressible- A number of diverse (Dharmas (3) (attributes)) existing in a substance (dharmī) cannot be expressed simultaneously; hence, with respect to this, the dharmī is inexpressible.
vācāmaviṣayamavācyam.
(Bhikṣu 6.10)
...yugapad aneka darmāpekṣayā ca avācyam...
(Bhikṣu 6.11)