pĕr-ăcerbus — Lewis & Short
pĕr-ăcerbus, a, um, adj.,
I very harsh to the taste.
I Lit.:
uva peracerba gustatu,Cic. Sen. 15, 53.—
II Trop., very painful:
mihi peracerbum fuit, quod, etc.,Plin. Ep. 6, 5, 6.