Definition of Monster: I think #2, #5 & #6 suffice for The Terminator.
mon·ster ( P ) Pronunciation Key (mnstr)
n.
1. An imaginary or legendary creature, such as a centaur or Harpy, that combines parts from various animal or human forms.
2. A creature having a strange or frightening appearance.
3. An animal, a plant, or other organism having structural defects or deformities.
4. Pathology. A fetus or an infant that is grotesquely abnormal and usually not viable.
5. A very large animal, plant, or object.
6. One who inspires horror or disgust: a monster of selfishness.