PRUNTY according to THE OXFORD NAMES COMPANION, has Irish origins- " Anglicised form of Gael. O' Proinntigh ' descendent of Proinnteach', a personal name meaniung 'Bestower' (originally a byname denoting a generous person). "
Interestingly, the name "BRONTE" as in the sisters, is a variant.
In the 1881 Census (excluding Ireland), there is a significant concentration in Scotland, around Dundee, Angus and Kincardineshire.
There is also a minor concentration around Stockport.