c.1386, from
pyss "urine" (in reference to the acrid smell of an anthill) +
mire "an ant," probably from O.N.
maurr "ant," perhaps distantly connected with Gk.
myrmex, L.
formica "ant." Cf.
pissant, also early Du.
mierseycke (from
seycke "urine"), Finn.
kusiainen (from
kusi "urine").
"He is an angry as a pissemyre,
Though þat he haue al that he kan desire."
[Chaucer]
Applied contemptuously to persons from 1569.