ETYMOLOGY
from dunce (n.) + -fy
EXAMPLE
“…I would gladly rid my hands of it cleanly if I could tell how, for what with talking of coblers, & tinkers, & roapemakers, and botchers, and durt-daubers, the marke is cleane gone out of my muses mouth, and I am as it were more than dunsified twixt diuinitie and poetrie…”
From: The Vnfortvnate Traveller
Or, The Life of Iacke Wilton
Thomas Nashe, 1594
Lexicophilia 