Many ISKCON websites call Adi Shankaracharya, Swami Vivekananda, Buddha and Ramakrishna Paramahamsa ''mayavadis'' and that Chaitanya Mahaprabhu called mayavadis ''greatest of all offenders''. However, I am unable to find the meaning of this term on the internet. What is the meaning of this term and is this term mentioned in any of the scriptures?
The earliest reference I can find is from the 8th century in Bhaskara's Bhasya on the Brahma Sutra. First see the remark made by Surendranath Dasgupta in the third volume of his History of Indian Philosophy:
Bhāskara argues against Śaṅkara as follows: the arguments that the upholder of māyā (māyāvādin) could adduce against those who believed in the reality of the many, the world, might be adduced against him also, in so far as he believes in monism (adraita). A person who hears the scriptures and philosophizes is at first under the veil of ignorance (avidyā); and, if on account of this ignorance his knowledge of duality was false, his knowledge of monism might equally for the same reason be considered as false. All Brahma-knowledge is false, because it is knowledge, like the knowledge of the world.
Note: Māyāvādī is the masculine nominative singular of the stem Māyāvādin (source).
Another book, “India & Beyond” details on Bhaskara’s definition and actually mentions the sourced reference:
Among the Vedāntins, Bhāskara (750-800) is probably one of the earliest critics against Śaṅkara. He called the Māyāvādin “one who depends on the doctrine of the Buddhist” (Bauddhamatāvalambin), and said that this position has been negated by the author of the Brahma Sūtra. (Bhāskara Brahmasūtra 2.2.29)
Afterwards, Yāmuna (918-1038), Rāmānuja (-1137), Madhva (1197–1276), Vallabha (1473-1531) and other Vedāntins severely criticized the Advaita Vedānta, pointing out that it is in essence nothing but a Buddhist doctrine.
Here is the relevant Sanskrit passage from Bhaskara’s Bhasya 2.2.29:
| ye tu bauddhamatāvalambino māyāvādinaste 'pyanena nyāyena sūtrakāreṇaiva nirastā veditavyāḥ |
So I guess it was Bhaskara who first coined and defined the term "Mayavadi" or "Mayavadin". Excluding of course potential non-extant earlier works.
Another scripture by Bhaskara using the word Mayavadin, is his commentary on the Bhagavadgita
Mayavada is the term coined by Chaitanya Mahaprabhu. Yes, I believe What Mahaprabhu has said because he is the realised soul. But, we must also see to whom and time period which made Chaitanya to say like that. Yes, I also believe this world is an illusion. That's what Vedas and Upanishads say "Brahman is the only truth and the world is illusionary". The moment we get realisation, We will come to know the useless of this world.
Coming back to question.
What is the meaning of the term ''Mayavadi''? Is the term mentioned in any of the scriptures?
No scriptures other than the life of Chaitanya says like that. If Advaita is Mayavada. Then whole Primary Upanishads and Vedas are Mayavadi Philosophy. especially, Chandogya Upanishad which is the primary Upanishad which Shankaracharya made the debate on with most sects goes wrong.
Tell me which thing in this world is not God. we worship the God which is made of rock. If we touch any person with foot, we immediately touch them and say sorry to yourself. If you are not Atman (which is indeed Brahman itself), why we do that?.
Hence, God is everywhere. What do everywhere mean? This earth is indeed mother earth herself. She is the Goddess. There is nothing called Mayavada or Brahmavada etc.
It is just one path. God is both form and formless. Water is formless. Take the form by becoming ice.
Mayavada is the philosophy which was established by Sripad Sankaracarya, in order to refute Buddhistic doctrine.
Mayavadis are the followers of Mayavada Philosophy.
The Mayavadis believe that the Supreme Truth is Brahman or spiritual energy which is unlimited, without form, qualities, or activity.
According to Mayavada philosophy, all living entities are one with Brahman, but at present, are covered by illusion, and therefore temporarily separated from Brahman.
When the illusion is gone, the living entity becomes again one with the Brahman and loses its identity.
The main idea is that everything is God, meaning that you too are God but somehow or other you forgot that you were God.
Out of this perspective, the Mayavadis neither accept the form nor the personality of Krishna as absolute but as the creation of Maya. Therefore, Sri Caitanya Mahaprabhu called the Mayavadis the biggest offenders of Krishna.