This verbal derivation of the substantive cuiture is unique to Anglo-Norman, but a cognate form is found in English about a century later.
v.n.
1pathol.med.to suppurate, become purulent, fill with pus:
(
c.1240; MS: s.xiii3/4
)
E quant la plaie quiture, si metez un drap sech en la plaie jesque la plaie seit desechié. [...] E des icel jor que la plaie comence a quiturer desque ele soit desechié i devez metre un neir oignement
i 48.ix
cuiturer (c.1240)