Meaning of word Anirvacanīya (अनिर्वचनीय) – Unutterable, indescribable, undefinable
Anirvacanīya is an adjective used for Maya. Maya is Indescribable, she is neither existent nor non-existent. She is beginning less but has an end only for the one who has realised the Self.
Adi Shankaracharya mentioned this word “Anirvacanīya” in Vivekachudamani verse 111 and Upadesha Sahasri verse 18
Vivekachudamani verse 111
सन्नाप्यसन्नाप्युभयात्मिका नो भिन्नाप्यभिन्नाप्युभयात्मका नो ।
साङ्गाप्यनङ्गाप्युभयात्मिका नो महाद्भुतानिर्वचनीयरूपा ॥ 111॥
English Meaning
Maya is neither existent nor non-existent nor both, Maya is neither same nor different nor both, Maya is neither neither composed of parts nor an indivisible whole nor both. She is most wonderful and cannot be described in words
Hindi Meaning
वह न सत् है न असत् है और न उभयरूप है; न भिन्न है न अभिन्न है और न उभयरूप है, न अंगसहित है न अंगरहित है और न उभयात्मिका ही है; किन्तु अत्यन्त अद्भुत और अनिर्वचनीयरूपा [जो कही न जा सके ऐसी] है !