The editor notes that in the manuscript, the word has an initial ‘p’ with an abbreviation mark and that the word could be read as purpender or even propender.
v.a.
1to spread out, spread widely:
(
1410-15; MS: c.1415-20
)
pur autrez bienfaitz innumerables a moy jusques en ça porpendez (Latin: aliis innumeris beneficiis michi actenus diffusis)426
porpender (1410-15)