The general meaning of Mahaprabhu is given as ‘Great Master.’ No doubt Sri Krishna Chaitanya Mahaprabhu is the ‘Great Master.’ Maha means great and prabhu means ‘Lord’ or ‘Master’.
Unfortunately it is sometimes the tendency of the conditioned souls in material existence to bestow the title ‘Mahaprabhu’ on a particular spiritual master. This is the case of Sri Vallabhacharya.
Vallabhacharya was closely associated with Sri Chaitanya and by the grace of the Lord he became a disciple of Gadadhara Pandita. Later on, after the death of their father, the sons of Vallabhacharya could not tolerate that their father had become a humble follower of Sri Chaitanya. Being envious of the fame and glory of the Lord, they decided to attribute the pastimes of Sri Chaitanya to Vallabhacharya. They successfully propagated their cult in a remote area of Southern Rajasthan where the pious souls had not yet heard of Sri Krishna Chaitanya Mahaprabhu. At that time, the sons of Vallabhacharya popularized their father as ‘Mahaprabhu,’ the ‘Great Master’ among the uninformed.
It has long since been a sensitive issue between the Gaudiya sampradaya and the Vallabha sampradaya. Should Sri Chaitanya alone be called ‘Mahaprabhu’ or is it a generic term befitting any and all ‘Great Masters’?
On the basis of the identity if Sri Krishna Chaitanya given in the sastra and sung by the acharyas (mahaprabhu sri chaitanya, radha-krishna nahe anya) it is Sri Chaitanya alone who is properly known as ‘Mahaprabhu.’ It is our humble opinion that not even vishnu-avataras or even Svayam-Bhagavan Sri Krishna of Goloka can be known as ‘Mahaprabhu’.
It is the words of Srila Krishna Dasa Kaviraja Gosvami as echoed by Srila Bhaktisiddhanta Sarasavati Thakura, mahaprabhu sri chaitanya, radha-krishna nahe anya, that gives us the hidden meaning of ‘Mahaprabhu.’
Radha and Krishna have appeared as one in the transcendental eternal form of Sri Chaitanya. Here ‘maha’ means Radharani who is also known as Mahabhava, and ‘prabhu’ means Rasaraja, or Krishna. Mahaprabhu means Rasaraja-Mahabhava. Rasaraja, the Supreme Enjoyer of rasa, the emporium of rasa, Sri Krishna. And Srimati Radharani, Mahabhava – the essence of hladini-sakti have appeared as one ‘Maha-Prabhu’ as Sri Krishna Chaitanya.
It is not possible for a jiva soul belonging to the marginal potency of Godhead at any time to attain to the position of the Supreme Lord, nor is it possible for the marginal potency to ever attain the ecstatic platform of maha-bhava. This alone is the position of Srimati Radharani.
Thus, Sri Krishnachandra has accepted the color and mood (maha-bhava) of Srimati Radharani and appeared as Sri Krishna Chaitanya to taste the sweet mellow of Her confidential service. Therefore, Sri Krishna Chaitanya is alone ‘Mahaprabhu’ and there can be no other.