Final answer:
Encroach, impinge, intrude, and poach are synonyms meaning to intrude on someone else's territory, while the antonym is 'stay in bounds'.
Step-by-step explanation:
Synonyms:
Encroach, impinge, intrude, and poach are synonyms because they all mean to intrude or trespass on someone else's territory. For example, if someone builds a fence that extends onto their neighbor's property, they are encroaching on the neighbor's land. Similarly, if someone breaks into a house without permission, they are intruding. Impinge and poach have similar meanings.
Antonym:
The antonym for these synonyms is 'stay in bounds'. This means to respect others' boundaries and not intrude or encroach on their personal space or property. For instance, if someone stays within the designated boundaries of a sports field during a game, they are staying in bounds.