Paññā-vimutti: 'deliverance through understanding' or understanding', signifies, according to Com. to A.V, 142, the understanding associated with the fruition of Nobility arahatta-phala In Pug. 31 and similarly in M. 70, it is said:;A Bhikkhu may not have reached in his own person the 8 liberations =jhāna, but through his understanding the fermentations have come to ceasing in him. Such a person is called understanding-liberated; paññā -vimutta. Com. to Pug.:;He may be one of five persons: either a practiser of bare insight sukha-vipassako, or one who has attained to Nobility after rising from one of the absorptions.; See S. XII, 7.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.