monster

Concise Oxford English Dictionary © 2008 Oxford University Press:
monster/ˈmɒnstə(r)/

▶noun

• 1 a large, ugly, and frightening imaginary creature.

  ■ an inhumanly cruel or wicked person.

  ■ humorous a rude or badly behaved child.

• 2 a congenitally malformed or mutant animal or plant.

• 3 [as modifier] informal extraordinarily large.

▶verb Brit. informal criticize severely.

– origin ME: from OFr. monstre, from L. monstrum ‘portent or monster’, from monere ‘warn’.